* At least 10 killed in rebel ambush
* Fighting intensified after plane crash (Adds details, quotes)
KIEV, Aug 1 (Reuters) - Pro-Russian separatists killed at least 10 Ukrainian paratroopers in an overnight ambush in the region of east Ukraine where a Malaysian airliner was brought down, government forces said on Friday.
The rebels said they had "captured good trophies" and pushed back government forces around the town of Shakhtarsk, where Kiev said a paratrooper unit moving from one base to another had come under mortar and tank fire.
Shakhtarsk is close to the rolling fields where Malaysia Airlines flight MH17 came down on July 17, killing 298 people, and fighting has raged around it for several days as the Ukrainian army tries to quell the separatist rebellion.
"Our troops were ambushed," Kiev's "anti-terrorist operation" said in a Facebook statement. "Ten Ukrainian servicemen were killed."
In other violence, city authorities said five civilians has been killed and nine injured in the past 24 hours in Luhansk, one of the two last big rebel strongholds.
Government forces have intensified their military offensive in mainly Russian-speaking east Ukraine since the airliner came down, forcing the rebels out of several other towns and pegging them back in Luhansk and Donetsk.
Luhansk, the smaller of the two cities, is now almost completely surrounded by government troops. It has been cut of from food supplies and left with no electricity or running water, residents say.
Rebel commander Igor Girkin declared a state of siege in the rebel-held territory in and around Donetsk, saying this allowed his fighters to confiscate cars, construction materials, food, medical equipment and phones.
The United Nations said in a report this week that more than 1,100 people had been killed and nearly 3,500 wounded between mid-April and July 26.
Kiev said its latest combat report that Russian aircraft had flown over east Ukrainian territory, the latest of several such accusations in the last few weeks, but Moscow has denied such reports.
The United States says the separatists probably shot down the Malaysian plane by mistake with Russian-made missile, but the rebels and Moscow deny the accusation and blame the crash on Kiev's military campaign to quell the uprising. (Reporting by Pavel Polityuk and Natalia Zinets, Writing by Gabriela Baczynska, Editing by Timothy Heritage)