KIEV accused Moscow today of involving itself in the conflict between government troops and rebels in eastern Ukraine after a military transport plane was shot down on the Russian border.

While rebel forces claimed responsibility for downing the Ukrainian government's Antonov-26, Ukrainian Defence Minister Valeriy Heletey suggested that the rocket had been fired from Russia.

Mr Heletey asserted implausibly that the plane had been flying at an altitude of 6,500 metres — too high to be reached by the separatists’ SAM-6 missiles.

The Kiev authorities said that plane may have been carrying around 20 people, but it transpired that all eight people on board had bailed out safely.

President Petro Poroshenko claimed earlier that the separatist forces were receiving substantial manpower and military equipment from Russia, which Moscow denies.

“In the last three days, Ukraine’s armed forces have been attacked with Russian multiple-rocket launchers,” he said after a meeting with his security officials.

President Poroshenko claimed to have evidence of Russian army officers’ involvement in the hostilities, but he did not elaborate.

Government forces have effectively halved the territory held by the separatists, who have retreated to strongholds around Lugansk and Donetsk. 

Both these overwhelmingly Russian-speaking regions have declared independence from the government in Kiev.

The Defence Ministry said yesterday that government troops had taken several villages around Lugansk and had reopened a corridor to its civilian airport.

Officials said that their troops now controlled several areas on the fringe of Lugansk, including Metallist, Oleksandrivsk, Bile and Rozkishne.

“Due to successful offensives by forces in the Donetsk region, some militants are trying to leave the city,” the ministry claimed, but rebels insisted that their fighting capabilities remain strong.

A spokeswoman for the Lugansk People’s Republic said that its forces had destroyed a pro-Kiev armed convoy in the village of Heorhiivka, six miles west of the airport, killing at least three soldiers.

The leader of the military wing of the insurgency, Igor Girkin, also known by his nom de guerre Strelkov, predicted a bitter fight for Lugansk at the weekend, saying that Ukrainian forces had deployed up to 70 tanks in the offensive.