Kerry calls on Russian FM to stop Ukraine attacks

 US Secretary of State John Kerry called his Russian counterpart Wednesday to urge him to stop separatist attacks on a strategic Ukrainian town and respect a fragile ceasefire, AFP reports.

Despite the fall of the eastern town of Debaltseve to pro-Russian rebels after a fierce assault, US officials said the truce brokered just last week was not yet dead.

Kerry spoke early Wednesday with Russian Foreign Minister Sergei Lavrov and pressed him "to stop Russian and separatist attacks on Ukrainian positions in Debaltseve and other violations of the ceasefire," State Department spokeswoman Jen Psaki said.

Hundreds of exhausted government troops retreated from the town -- a strategic railway hub sandwiched between the main rebel-held cities of Donetsk and Lugansk -- as the separatists claimed to be in total control.

The town's fall deals a heavy blow to the European-brokered truce agreed to by all sides in the Belarus capital Minsk last week and endorsed by the UN Security Council on Tuesday.

But Psaki said the ceasefire remained in play, and there had been some signs that in other areas "the quantity and intensity of attacks has decreased."

"We don't consider it is dead, no," she told reporters.

"We've also seen reports of the withdrawal of certain types of heavy weapons in various parts of Donetsk and in Lugansk by both separatists and Ukrainian government forces," she added.

She cautioned that without access by OSCE monitors the US could not confirm the reports.

"Right now, we believe we still need to continue to give time for the agreement to work itself through," Psaki said, adding Washington was focused on how it could help implement the ceasefire.

"Obviously, there are some violations. And is it perfect? No. But we don't think the alternative or the right option is to take steps that would hurt the implementation of agreement."

Some congressional Republicans meanwhile blasted Washington and Western governments for clinging to hopes the peace deal will bear fruit, instead of hardening their position on Russian President Vladimir Putin and swiftly providing lethal weapons to Ukrainian forces.

Debaltseve's fall "should be all the evidence we need to proclaim the failure of the recent ceasefire agreement in Ukraine," hawkish Senators John McCain and Lindsey Graham said Wednesday in a statement.

"Persisting with the illusion of a ceasefire will only give Putin the cover he wants to plan his next act of aggression inside of Ukraine."

On Tuesday, the two senators accused German Chancellor Angela Merkel and French President Francois Holland, backed by US President Barack Obama, of "legitimizing the dismemberment of a sovereign nation in Europe for the first time in seven decades."