One week into office and facing the largest loss of life among Ukraine's forces in a single attack by separatists, the country's new president met Saturday with his security chiefs and called on them "to regain Ukrainian control over the state border and give a resolute response to terrorists."
The meeting, reported on President Petro Poroshenko's website, came after a military transport plane was shot down late Friday by pro-Russia separatists near the eastern industrial city of Luhansk. All 40 servicemen and nine crew members on board were killed, officials said.
The Ukrainian Defense Ministry reported that the IL-76 transport plane took antiaircraft and machine gun fire. "The plane fell in a farm field near the airport, exploded and burned," said ministry spokesman Vladislav Seleznev.
Poroshenko, who took office after a special election was called to replace ousted pro-Russia President Viktor Yanukovich, declared Sunday a day of mourning, adding that those involved in the attack "will certainly be punished."
"Ukraine needs peace, but terrorists will get a response they deserve," he said.
In another incident, five Ukrainian border guards were killed and seven wounded Saturday morning when their convoy ran into an ambush near Mariupol in the Donetsk region, the border guards service reported in a statement posted on its website. Ukrainian forces retook the industrial port city on the Sea of Azov from separatists on Friday.
During Poroshenko's meeting with military, security and law enforcement chiefs, acting Defense Minister Mykhailo Koval reported that in the previous 24 hours more than 250 pro-Russia gunmen had been killed in the military's operations designed to regain control of areas in eastern Ukraine seized by fighters in the last two months. The separatists in Russian-speaking areas of the east and south are opposed to the new central government in Kiev and in some cases hope to unify with neighboring Russia.
The servicemen killed in the downed aircraft were members of Dnepropetrovsk Airborne Forces Brigade No. 25 and the nine crew members were from a Melitopol air force unit, Anatoly Hrytsenko, a lawmaker and former defense minister, wrote on his Facebook page.
Earlier Saturday a representative of the self-proclaimed Luhansk People's Republic, which in May declared independence from Ukraine, told the Russian news agency RIA Novosti that its fighters shot down a military plane over the city's airport.
Pieces of three Russian-made portable antiaircraft rockets were found near the airport with an empty can of Russian-made meat preserves, Ukraine military expert Dmitry Tymchuk wrote on his Facebook page.
Luhansk and most of the surrounding region are under the control of pro-Russia gunmen, but the airport is still in the hands of government forces, which regularly repel separatist attacks, reports say.
Ten trucks suspected of carrying Russian mercenaries arrived in Luhansk during the night after crossing the border with Russia, a large stretch of which is also under the separatists' control, UNIAN news agency reported Saturday.
Earlier last week, three T-64 tanks and several armored personnel vehicles crossed the Russian border into Ukraine in the neighboring Donetsk region, Ukraine officials said.