Russia is launching artillery attacks from its soil on Ukrainian troops and preparing to move heavier weaponry across the border, the U.S. and Ukraine charged Friday in what appeared to be an ominous escalation of the crisis.
Russia accused Washington of lying and charged Ukraine with firing across the border on a Russian village. It also toughened its economic measures against Ukraine by banning dairy imports.
Andriy Lysenko, a spokesman for Ukraine's National Security and Defence Council, said five salvos of heavy rockets were fired across the border near the town of Kolesnikov in the Lugansk region in the country's east. A border crossing point near Marynovka was fired on twice with mortars, also from the Russian side, while Ukrainian forces shot down three Russian drones, Lysenko said.
If true, the allegations mean Moscow is playing a more direct role in the fighting than it has been accused of up to now — a dangerous turn in what is already the gravest crisis between Russia and the West since the end of the Cold War.
In addition, Col. Steve Warren, a Pentagon spokesman, said that the U.S. has seen powerful rocket systems moving closer to the Ukraine border. They could be put into the hands of the Russian-backed separatists as soon as Friday, he added, saying "it's that close" to the border.
It wasn't clear what those developments mean for the international investigation into the downing of Malaysia Airlines Flight 17. U.S. authorities believe the separatists shot it down with a missile, perhaps in the mistaken belief it was a military plane.
A small group of Dutch and Australian investigators combed the sprawling, unsecured field where the plane came down on July 17, taking notes and photos as their governments prepared police detachments they hope can protect the crash site and help bring the last of the 298 victims home.
Col. Warren also corroborated Ukrainian reports of artillery fire from Russia. He said there was no indication Ukraine had shelled Russia.
"For the last several days Russian forces using Russian artillery from Russian soil have conducted attacks against Ukrainian military positions in Ukraine," Col. Warren said. "This is unquestionably an escalation from a military perspective."
Russia's Foreign Ministry responded to U.S. allegations about cross-border shelling by saying: "Facts and details to confirm these lying contentions do not exist."
Russian authorities, however, accused Ukraine of trying to kill law enforcement officials who were checking reports of cross-border shooting on Friday by firing a volley of mortar rounds over the frontier into Russia.
A Russian security official said up to 40 mortar bombs fired by Ukrainian forces had fallen in the Russian province of Rostov near the border where Ukrainian government forces are fighting pro-Russian separatists. There were no reports of injuries.
"Those who shot from Ukraine carried out the shooting purposefully with an intent to kill Russian law enforcement officials," said Russia's Investigative Committee, which answers only to President Vladimir Putin.
"It was only the poor preparation of the Ukrainian military and the timely evacuation of law enforcement officers under the cover of armoured transport vehicles that did not allow the shooters to realize their intention," it said in a statement.
Moscow traditionally views Ukraine as within its sphere of influence and has been angered by the Kiev government's moves to build links with western Europe. But it denies supplying weapons to the separatist forces and on Friday accused the Ukrainian military of firing up to 40 mortar rounds across the border.
The allegations come amid a Ukrainian government offensive against the separatists that has won back control of several important towns over the past few weeks.
Douglas Lute, U.S. ambassador to NATO, accused Russia of waging "civil war by proxy" in Ukraine and said the Russians have about 15,000 troops massed near the border. He spoke at a security forum in Aspen, Colorado.
European Union ambassadors, meanwhile, reached a preliminary deal Friday on stepped-up sanctions against Russia for its involvement in Ukraine, targeting Moscow's defence and technology sectors and its access to European capital.
EU spokeswoman Maja Kocijancic said EU member states must decide whether the measures need to be approved by a summit meeting of the trade bloc's 28 member countries to go into effect.
The ambassadors also ordered asset freezes and travel bans against 15 more Russians and pro-Russian Ukrainians accused of undermining Ukraine. Eighteen businesses or other entities will also be subject to sanctions.
Russia increased its economic pressure on Ukraine when its agency in charge of agricultural products announced that it is banning imports of Ukrainian dairy.
Russia is the biggest export market for Ukrainian milk and cheese.
With a report from Reuters