KIEV, Feb. 16 – The United States said it was "gravely concerned" by the fighting in and around the town of Debaltseve in eastern Ukraine after a ceasefire agreement that came into force on Sunday, Reuters reported.

The U.S. also said it was closely monitoring reports of a new column of Russian military equipment moving toward the region.

"These aggressive actions and statements by the Russia-backed separatists threaten the most recent ceasefire," U.S. State Department spokeswoman Jen Psaki said in a statement. "We call on Russia and the separatists it backs to halt all attacks immediately."

Ukraine's military said separatist rebels had shelled a district of Donetsk city in east Ukraine at around 1000 GMT on Monday despite a ceasefire.

"Terrorists opened fire from heavy weapons on the city of Donetsk. The shelling affected the district of Panfilovka," the military said in a post on Facebook.

It said its own forces were not involved in any shelling of Donetsk. "The Ukrainian forces are strictly observing the ceasefire," it added.

Fighting subsided in many parts of eastern Ukraine under a ceasefire deal reached last week in marathon talks involving the leaders of France, Germany, Russia and Ukraine.

But the truce appears to have been stillborn in Debaltseve, where the most intensive fighting has taken place in recent weeks.

"The situation is fragile," said German Chancellor Angela Merkel, the driving force behind the deal reached on Thursday after all-night talks in the Belarussian capital Minsk.

"It was always clear that much remains to be done. And I have always said that there are no guarantees that what we are trying to do succeeds. It will be an extremely difficult path," she told reporters in Berlin.

Merkel, along with the leaders of France and Ukraine, expressed concern about continued fighting in Debaltseve and said observers from the Organization for Security and Cooperation in Europe (OSCE) must have "free access" for their work in eastern Ukraine.

Rebels said soon after the ceasefire came into effect they had no intention of observing it at Debaltseve, where they have been advancing since January and now have a Ukrainian unit all but encircled.

Washington says the rebel operation around the town, which sits on a strategic railway hub, is being assisted by the Russian armed forces, which Moscow denies.

The U.S. State Department spokeswoman called on Russia and the separatists to engage with the OSCE to facilitate the cease fire.

The OSCE said on Sunday that the rebels had refused to allow its monitors to reach Debaltseve after the ceasefire took effect.
Reuters reporters near the front said Debaltseve was being relentlessly bombarded with artillery. At least six tanks as well as armored personnel carriers and artillery could be seen in woods near Vuhlehirsk, 10 km (six miles) west of Debaltseve, which the rebels captured a week ago.

Military trucks headed along the main road in the direction of the town to regular bursts of shelling and the firing of Grad rockets and machine guns.

"You can hear there is no ceasefire," said a rebel fighter with a black ski mask who gave his name as Scorpion, his nom de guerre, and blamed the fighting on Kiev's forces. "Debaltseve is our land. And we will take Debaltseve."

Kiev said its forces had been shelled more than 100 times in eastern Ukraine since the truce took effect, five of its servicemen had been killed and 25 wounded, and that it could not carry out an agreement to pull back big guns in such conditions.
"The pre-condition for withdrawal of heavy weapons is fulfilling Point One of the Minsk agreements - the ceasefire. One hundred and twelve attacks are not an indicator of a ceasefire," said a Kiev military spokesman, Andriy Lysenko. (rt/ez)