* President says Russia conducts "direct and open
* Concerns grows over fate of troops in Ilovaysk
* Search for missing seamen after boat attack
* Fighting goes on for control of Luhansk airport
(Adds background, details of fighting)
By Richard Balmforth and Pavel Polityuk
KIEV, Sept 1 Ukraine's military said on Monday
its forces were battling a Russian tank battalion for control of
a vital airport in the east of the country as President Petro
Poroshenko accused Moscow of "direct and open aggression"
against his country.
Ukrainian coastguards meanwhile searched for two seamen
missing after one of their patrol boats was sunk in the Sea of
Azov by artillery fire from pro-Russian separatists on the
Eight other seamen survived Sunday's attack and were being
treated for wounds and burns, a border guard official said.
Several hundred Ukrainian forces are bogged down near
Ilovaysk, east of the region's main city of Donetsk, and have
been trying to break out of encirclement by Russian-backed
separatists for several days.
Poroshenko, speaking at a military academy in Kiev, said
Russia's direct involvement in the war against the separatists
in eastern Ukraine had tipped the balance on the battlefield and
was the main reason for recent reversals.
"Direct and open aggression has been launched against
Ukraine from a neighbouring state. This has changed the
situation in the zone of conflict in a radical way," he said.
Poroshenko said there would be changes in the military top
brass because of the events of last week.
Last week separatists who Kiev says were backed by a Russian
armoured column took the town of Novoazovsk in the southeast and
are now threatening the strategic port city of Mariupol.
Despite growing concerns, Kiev's military has imposed an
information clampdown on what is happening in Ilovaysk until its
forces have been successfully withdrawn.
But Anton Gerashchenko, an interior ministry adviser, told
Ukraine TV's 112 channel: "The tragedy near Ilovaysk became
possible after (Russian President Vladimir) Putin brought
regular troops into Ukraine."
"In all there were 500 men deployed in Ilovaysk. The
Russians came with superior forces, fresh, healthy and with a
full ammunition set," he said.
"Our people surrendered only when they had run out of
ammunition, when they no longer had anything to fire with," he
said. In the past 24 hours, 69 more pro-government fighters had
managed to break out and rejoin Ukrainian forces, adding to a
few dozen others over the weekend.
Fighting continued to rage near Luhansk, the region's other
main city, for control of the main civilian airport just to its
south, the military said in a statement.
"Ukrainian paratroopers are fighting a tank battalion of the
Russian armed forces to hold the airport," it said.
In the past 24 hours, the separatists had lost 80 fighters,
some armoured vehicles and a missile system. The military gave
no figures for Ukrainian losses.
Ukrainian border guards said search operations were still
going on for the two missing coastguards whose patrol boat was
hit by a rebel shell, in what pro-Russian rebels claimed was the
first sea victory of their five-month separatist war.
The boat was hit in the Sea of Azov, the area where rebels
are now threatening the main port of Mariupol.
"The cutter has sunk. We managed to save eight sailors,
thanks to other cutters coming to their rescue. Seven of them
are injured or burned. Two sailors have gone missing. We are
continuing rescue operations," the official, Serhiy Astakhov,
"After analysing the situation, we believe that this attack
was from an artillery system but we don't know yet where it was
fired from," he said.
A top United Nations human rights official said last week
that the total death toll in the five-month conflict - including
civilians, Ukrainian forces and separatists - was nearly 2,600.
(Reporting by Pavel Polityuk; Writing By Richard Balmforth;
Editing by Gareth Jones)