(Repeats story, text unchanged)
* Rivals exchange rockets, Grad missiles over Tripoli
* Roots of conflict back in 2011 civil war on Gaddafi
* Western powers worried Libya is becoming failed state
By Patrick Markey and Aziz El Yaakoubi
TRIPOLI, July 31 Booms of outgoing artillery
shaking the ground, militia fighters from the remote Libyan
mountain town of Zintan hunker down in the passenger terminal to
defend Tripoli airport, the biggest prize in the capital.
Across the city a few kilometres away, a commander of a
brigade from the port city of Misrata rallies his men to take
the airport back.
Three years ago, Zintani and Misratan rebel brigades
descended simultaneously on Tripoli from east and west to storm
the palaces of Muammar Gaddafi. Now, fighters from the two towns
are waging open war in the capital.
"This war is harder than the revolution," said Mohammed, a
fighter in a unit allied to the Zintanis, standing in the debris
of the airport terminal, dark smoke billowing from a nearby
blast. "They want to take the airport, and when you take the
airport you take Tripoli."
Across the city at his Tripoli base lined with tanks and
trucks mounted with cannons, Hassan Shakka, a commander of
Misrata's Central Shield brigade, said his forces were
"completing the revolution".
"We are not fighting the Zintanis: we are fighting the
remains of Gaddafi's army," he said. "There will be no ceasefire
until they leave Tripoli."
Two weeks of shelling have knocked Tripoli International
Airport out of commission. A control centre is damaged, nearly
20 jets parked on the tarmac have been hit, burned or destroyed
and the passenger terminal sports a gaping hole in its roof.
Grad missiles roar over the city. Fighters have closed off
parts of southern Tripoli with blockades and earth barricades.
Apartment blocks on the airport road bear bullet and blast
marks. Zintan fighters have set up checkpoints on the empty
highway where blackened grassland marks recent shelling. More
are dug in by the airport with anti-aircraft canons.
"It can still be contained. There is room to negotiate. But
it is a very delicate situation," said one Libyan government
official. "We are trying to negotiate to slow things down. If it
spins too much, you can't stop it and it becomes a hurricane."
The war for Tripoli's airport is not even the only war being
fought in Libya. A day's drive away in Benghazi, Libya's second
biggest city, followers of a renegade former Gaddafi general are
waging street battles against an alliance of militia groups,
including Islamist fighters that Washington blames for killing
the U.S. ambassador two years ago.
The Benghazi militia alliance has overrun a special forces
base and forced irregular forces and the army to retreat.
The collapse of Gaddafi's four decades of single man rule
has left Libya an armed free-for-all, where cities, regions,
charismatic individuals, urban neighbourhoods and rural tribes
all field their own armed forces.
Towns fight towns; Islamists oppose nationalists;
federalists rise up against central government; ex-Gaddafi units
clash with former revolutionaries - and everyone has guns,
artillery, tanks and missiles, taken from the vast arsenals the
deposed dictator had stashed across the country.
Western countries, which helped blast Gaddafi out of power
with a NATO bombing campaign in 2011, are mostly getting out,
shutting and evacuating embassies as the OPEC oil exporter
teeters toward becoming a failed state.
With the main airport shut, the Americans left by road
escorted by Marines; the French sailed out by sea.
For the past three years, the central government has largely
failed to build a national army, instead buying off the loyalty
of armed groups by putting individual fighters or whole militia
units onto the payroll. Despite taking the government's money,
most remain loyal to their commanders, regions or cities.
U.N., U.S. and European special envoys are pushing for a
ceasefire and political settlement around a new parliament due
to start its work in August. But the negotiations are difficult.
Each brigade claims to be a legitimate armed force
authorised by competing factions within ministries or the
previous parliament; each claims the entitlement as
revolutionary liberators of the capital, and refuses to give up
its Gaddafi-era heavy weaponry.
Since the 2011 war, Libya's factional rivalries have flared
before, only to be restrained by a tenuous balance of power that
Libyan officials and diplomats say comes from the knowledge that
neither side can overcome the other.
For now, the main rivalry in the capital is that between
Zintan and Misrata, which both played outsized roles in the 2011
war that unseated Gaddafi and parlayed their victory into status
as kingmakers in the capital.
Zintan, a rugged Arab garrison town of barely 50,000 people
perched among poor Berber villages in the arid heights of the
Western Mountains, led an unlikely campaign against much larger
Gaddafi forces, bursting through the front to reach the coast
and march on Tripoli in a lightning advance. Its militia later
captured Gaddafi's son Saif al-Islam, still held in its jail.
Misrata, a thriving port of nearly 300,000 with a mercantile
tradition, was the biggest city in the west to hold out against
Gaddafi's forces, keeping the revolution's hopes alive under
intense bombardment during a months-long siege, before its
forces battled their way to the capital.
When Tripoli fell, Misrata and Zintan brigades both rushed
in from opposite sides to lay claim to stakes in the capital.
Zintan took the civil airport; Misrata and its allies took a
military airbase. Since then they have skirmished in turf wars.
Despite their local origins, the militia of both towns have
allied themselves to political factions with national ambitions.
The Zintanis, with allied groups called the Qaaqaa and
al-Sawaiq brigades which include some former Gaddafi special
forces, have sided with the National Forces Alliance, led by
Mahmoud Jibril, an interim prime minister after the war.
Zintanis have long complained of their town's neglect by
Gaddafi, and say they missed out on Libya's oil wealth. Rivals
say they have grown rich from exploiting control of the airport.
Many of the Qaaqaa brigade members are fiercely opposed to
what they see as growing Islamist influence in Libya.
On the opposite side, the Misrata brigades, including "Libya
Shield" units created by parliament, are allied to
Islamist-leaning militias whose allegiance is with the Justice
and Construction party, seen as close to the Muslim Brotherhood.
The depth of Misrata's suffering under siege by Gaddafi's
forces has become a rallying cry for fighters who accuse the
Zintanis of cooperating with ex-Gaddafi figures.
"The revolution didn't finish. It is about perceptions over
the future of the country. They both think they can win, but do
they go to the brink?" said one Western diplomat. "The hope is
that they realise that no side can win."
Opponents of the Islamists blame them for starting the
latest violence to scuttle the start of the new parliament,
elected in June under a system that required candidates to stand
without party affiliation, which cost Islamists some clout.
"What is happening is an attempted strike against election
results, which handed more power to the Islamists' enemies,"
said Ziad Dgheim, a federalist and member of the new parliament.
Now each blames the other as positions harden. Zintan says
it is only defending the airport from attack and urged a
ceasefire to stop "Libyan blood being spilled."
Ahmed Hadia, spokesman for the Misrata Central Shield
Brigade, said his group joined the battle only after Zintan's
Qaaqaa and Sawaiq brigades were accused of trying to stage a
coup and the government was not strong enough to respond.
The airport struggle is hardly the first time Libya's armed
factions tried to decide Libya's future. The last parliament and
ministries were repeatedly stormed by armed groups to make
demands on the fragile state.
The government blames one Islamist militia for the
kidnapping of the prime minister from his hotel room in Tripoli
last year. Another federalist ex-rebel blockaded Libya's oil
ports for a year to demand more autonomy for the east, halting
the exports that form the government's lifeblood.
But Professor Dirk Vandewalle, a Libya expert at Dartmouth
College in the United States, said militias had now crossed a
threshold by openly attacking institutions like Tripoli airport
that before would have been viewed as out of bounds.
"What the militias are saying is we are willing to do
whatever it takes to solve this," he said. "This is much more
visceral, and it is about the spoils of the state and who will
control them. A much larger battle is starting to evolve."
(Additional reporting by Ahmed Elumami and Feras Bosalum in
Benghazi; Editing by Peter Graff)