Ukraine's president, Petro Poroshenko, on Saturday (June 14) promised a tough response on Saturday to pro-Russian separatists who shot down an army transport plane, killing 49 servicemen and dealing a blow to a military campaign to crush their uprising.

Poroshenko's words came as protesters were seen pelting the Russian embassy in Kiev with eggs and bricks, while witnesses said they were also ripping up a Russian flag in protest at what they called Moscow's backing of separatist rebels in east Ukraine.

In a video handed out from the president's office, Poroshenko was seen on camera saying every effort to find out what was happening was being made.

"We will do everything possible so that those who are guilty in the deaths of soldiers will be found, terrorist will receive adequate response and will be punished," he said.

"I entrusted Armed Forces of Ukraine with the most important task to regain control over the state border of Ukraine which is being used by terrorists for receiving weapons, military vehicles, reinforcing, and money," he added.

The newly-installed Petro Poroshenko summoned security chiefs for consultations after the plane was hit by an anti-aircraft missile as it came in to land at an airport outside the city of Luhansk, a centre of the rebellion in east Ukraine.

The Kiev crowd protesting at the embassy, formed of more than 100 mostly young people, many of them with their faces covered, held up banners with slogans such as "Russia go home".

The demonstrators then overturned several cars, including some which appeared to belong to the embassy, and damaged the metal gate but police did not intervene.

"If the Ukrainian Foreign Ministry doesn't want to admit that they are working for the enemy, they have immediately to break off diplomatic relations with Russia, and proclaim Putin's regime an aggressor," an unnamed protester shouted through a loudspeaker.

Ukraine accuses Russia, which annexed the Crimea region from Ukraine in March, of supporting the uprising in Russian-speaking regions in the east and the United States has accused Moscow of providing the rebels with tanks. Russia denies the accusations.

The protest followed the deaths of 49 Ukrainian servicemen on board a military transport plane that was shot down by the separatists early on Saturday.

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