The attack, which began in the early morning hours, involved as many as 500 pro-Russian rebels armed with mortars and rocket-propelled grenades, a spokesman for the Ukrainian border service said.
The fighting took place in Luhansk, a major eastern Ukrainian city only miles from the Russian border, which separatists recently declared part of a sovereign republic.
Seven border service officers were injured and five rebels were killed in the ongoing fighting as of midday Monday, said Oleg Slobodyan, the border service spokesman.
Slobodyan said the insurgents fired on Luhansk’s border control headquarters from adjacent apartment towers, making it difficult for troops to return fire without injuring civilians.
Ukrainian fighter jets destroyed two mortar positions manned by militants, Vladislav Selezniov, a spokesman for the Ukranian military said.
During the air offensive, the militants sought cover in neighboring houses.
After the planes left, the rebels returned to their positions and resumed shooting, he said.
“They want to clear the way to the border,” Slobodyan said.
“If they capture that building, they control all the posts along the border.”
The conflict between Ukrainian government forces and pro-Russian insurgents has escalated sharply since the country’s May 25 election, which saw Petro Poroshenko, one of Ukraine’s richest men, win convincingly in the first round.
Pro-Russian rebels disrupted voting in the embattled east of the country, where polling largely did not take place.
After the election, the rebels attempted to seize Donetsk’s international airport, causing a fierce two-day gun battle for the installation last week that resulted in a heavy loss of life for the separatists.
The rebels then shot down a Ukrainian military helicopter, killing several government forces, including a general.
The U.S. views the Monday morning Luhansk attack with “great concern,” said Derek Chollett, a Department of Defense Assistant for International Security, who is in Kiev meeting with senior Ukrainian officials.
“It’s a further example of the destabilizing activities supported by Russia in the east, and it’s something we strongly condemn,” he said.
The United States and the West have accused the Kremlin of fomenting and arming the unrest in eastern Ukraine.
Russian Foreign Minister Sergei Lavrov told reporters in Moscow that Russia will submit a draft resolution addressing the crisis in Ukraine to the U.N. Security Council on Monday.
“We are very concerned about what is going on,” he said.
“People die every day and civilians suffer increasingly. The army, combat aviation and heavy weapons continue to be used against them,” Lavrov said, according to Russia’s Interfax news agency.
Lavrov blasted the Western media for what he described as biased coverage of the conflict.
Russia’s energy ministry confirmed it has received $786.4 million from Ukraine’s Naftogaz for gas deliveries, which will stop Russia from cutting off natural gas to the violence-wracked country for this week.
The partial payment comes as Russian leaders showed they were prepared to squeeze their struggling neighbour economically, even as Russian citizens take an increasingly open role in the violent conflict in the east.
Alexei Miller, CEO of Russian energy giant Gazprom, told reporters that Ukraine would have to start paying for its gas supply in advance and that the remaining $2.237 billion owed to the company needed to be paid before June 9.
Newly elected Ukrainian president Poroshenko, 48, a billionaire who made his fortune in the confectionary business, has promised to crush the separatists, who have seized government buildings around the embattled east of the country.
He also said he wanted to talk to Russia, who he called crucial to any peace in the east.
He’s also promised closer ties with the West.
How he might accomplish all three was not immediately clear with the escalation of violence between the separatists and government forces on the ground since he was elected.
Poroshenko is due to be sworn in June 7.
Source: The Washington Post