* Kiev says flag raised over police station in city of
* No confirmation of Luhansk advance from separatists
* Separatists shoot down Ukrainian fighter jet
* Russian, Ukrainian foreign ministers to meet in Berlin
* Part of Russian aid convoy moves towards Ukraine
By Natalia Zinets and Thomas Grove
KIEV/DONETSK, Ukraine Aug 17 Ukrainian forces
have raised their national flag over a police station in the
city of Luhansk which was for months under rebel control, Kiev
said on Sunday, in what could be a breakthrough in Ukraine's
efforts to crush pro-Moscow separatists.
Ukrainian officials allege though that the rebels are
fighting a desperate rearguard action to hold on to Luhansk --
which is their supply route into neighbouring Russia -- and say
the flow of weapons and fighters from Russia has accelerated.
The foreign ministers of Ukraine and Russia were preparing
to meet for talks on the conflict in Berlin on Sunday, though it
seemed likely that the diplomacy could be overshadowed by
fast-moving developments on the battlefield.
Russia denies helping the rebels and accuses Kiev, backed by
the West, of triggering a humanitarian crisis through
indiscriminate use of force against Russian speakers in eastern
Ukraine who reject the Ukrainian government's rule.
Andriy Lysenko, a Ukrainian military spokesman, said
government forces fought separatists in a neighbourhood of
Luhansk city on Saturday and took control of the Zhovtneviy
neighbourhood police station.
"They raised the state flag over it," Lysenko told a news
Separatist officials in Luhansk could not be reached by
telephone, and a separatist spokeswoman in Donetsk, the other
rebel strong-hold in eastern Ukraine, said she did not know what
had happened in Luhansk.
A photograph posted on Twitter appeared to show a Ukrainian
flag on the front of the police station, but it could not be
independently verified. pic.twitter.com/fhzEPyUpMp
If confirmed, the taking of the police station is
significant because the city of Luhansk has for several months
been a rebel redoubt where Kiev's writ has not run.
Ukrainian troops have been closing in on the city from the
outskirts, but had not previously been able to get forces inside
the city limits. The separatists still control sections of the
border linking Luhansk region to Russia.
The four-month-old conflict in Ukraine's Russian-speaking
east has reached a critical phase, with Kiev and Western
governments watching nervously to see if Russia will intervene
in support of the increasingly besieged rebels.
The rebels have responded to the reverses with defiant
rhetoric, and the fighting continues.
Ukrainian authorities said on Sunday that the separatists
shot down a Ukrainian warplane. The pilot ejected and was
located and recovered after a search, a military spokesman,
Oleksiy Dmytrashkivsky, told Reuters.
On Saturday, Alexander Zakharchenko, prime minister of the
self-proclaimed Donetsk People's Republic, said rebels were in
the process of receiving some 150 armoured vehicles, including
30 tanks, and 1,200 fighters trained in Russia. He said they
planned to launch a major counter-offensive.
"They are joining at the most crucial moment," he said in a
video recorded on Friday.
The assertion that the fighters were trained in Russia is
awkward for Moscow, which has repeatedly denied allegations from
Kiev and its Western allies that it is providing material
support to separatist fighters.
In a sign of concern at the latest rebel comments, German
Chancellor Angela Merkel and Ukrainian President Petro
Poroshenko agreed in a phone call on Saturday that deliveries of
weapons to separatists in Ukraine must stop and a ceasefire must
be achieved, a German government spokesman said.
The Ukraine crisis has dragged relations between Russia and
the West to their lowest point since the Cold War and set off a
round of trade restrictions that are hurting struggling
economies in both Russia and Europe.
Adding to the tensions, Russia and Ukraine have been at
loggerheads for days over a convoy of 280 Russian trucks
carrying water, food and medicine.
It was despatched by Moscow bound for eastern Ukraine but
has been parked up for several days in Russia near the border.
Kiev has said the convoy could be a Trojan Horse for Russia
to get weapons to the rebels, a notion that Moscow has dismissed
as absurd. It said the aid is desperately needed by civilians
left without water and power and under constant bombardment from
the Ukrainian advance.
After days of wrangling between Kiev and Moscow, there were
signs of movement on Sunday.
Sixteen trucks separated from the main convoy and drove into
a Russian bus depot near a border crossing into Ukraine, a
Reuters cameraman said from the scene.
The International Committee of the Red Cross said in Geneva
that Russian and Ukrainian border guards and customs officials
had agreed that the cargo could be inspected.
Ukrainian officials have painted a picture of a separatist
force that is on the run and starting to panic - though rebel
fighters Reuters reporters have spoken to in Donetsk say they
are determined to stand firm.
The Ukrainian National Guard said its forces had seized a
rebel field commander from Luhansk region as well as 13 others
suspected of "terrorist activity".
"The terrorists are putting on ordinary clothes, taking only
their passport with them and are trying to pass themselves off
as ordinary peaceful citizens on public transport to try to get
through the Ukrainian checkpoints," the National Guard said.
In the past week, three senior rebel leaders have been
removed from their posts, pointing to mounting disagreement over
how to turn the tide of the fighting back in their favour.
The fighting has taken a heavy human toll.
The United Nations said this month that an estimated 2,086
people, including civilians and combatants, had been killed in
the conflict. That figure nearly doubled since the end of July,
when Ukrainian forces stepped up their offensive and fighting
started in urban areas.
In Donetsk which like Luhansk is now ringed by Kiev's
forces, artillery fire has struck apartment buildings, killing
and wounding residents, according to Reuters reporters.
Officials in Kiev deny they are firing heavy weapons at
(Writing by Richard Balmforth and Christian Lowe; Editing by