The United States and the European Union have taken a firm but cautious stance on Ukraine as it hangs in the East-West balance even while Russia has felt free to be more combative, analysts say.

In a declaration Tuesday, foreign ministers of the 28 NATO member states, including US Secretary of State John Kerry, took a moderate line as mass protests continued in Kiev after the government abandoned a planned association accord with the European Union.

"We urge the government and the opposition to engage in dialogue and launch a reform process," NATO said.

In response to a police crackdown on pro-Europe protesters at the weekend, the statement added that NATO condemned the "use of excessive force against peaceful demonstrators in Ukraine."

Russian Foreign Minister Sergei Lavrov denounced the NATO declaration as unwarranted interference in Ukraine's domestic affairs, but analysts said it was a mere restatement of the West's position.

"The tone of the declaration is rather moderate," said one European diplomat.

"This is about trying to avoid upsetting Russia just as we are working well together on the Iranian nuclear issue and destroying Syria's chemical weapons arsenal," the diplomat said, asking not to be named.

For Lavrov, however, the declaration was out of place and part of outside efforts to muddy the waters in Ukraine.

"I do not understand why NATO adopts such statements," Lavrov said after a meeting Wednesday of the NATO-Russia Council, part of a two-day meeting of alliance foreign ministers.

"It helps to create a distorted picture and sends a wrong signal which may cause wrong understanding," he said.

Whether Ukraine seeks closer ties with the European Union is "a domestic issue," he added.

President Viktor Yanukovych dropped the accord just before a high-profile summit with the EU last week after Russia made clear the former Soviet state would pay a high price for deserting Moscow's fold.

The decision sparked street demos in Kiev and dismay in Brussels, which saw the association deal as a major achievement in bringing Eastern Europe closer to the EU.

Not a zero-sum game

For his part, Kerry was careful not to stoke tensions further, perhaps mindful of Moscow's charge that outside influences are seeking to destabilise Ukraine.

"Europe and Europe's friends all decline to engage in a rather overt, and we think, inappropriate bidding war with respect to the choice that might or might not be made" by Ukraine, Kerry said at the NATO foreign ministers meeting on Tuesday.

But Kerry also made clear that Washington remains concerned and unhappy about events, by cancelling a trip to Kiev to attend an OSCE meeting there on Thursday.

Instead, he chose to continue on to Moldova, the tiny former Soviet state which alongside Georgia opted to sign partnership deals with the EU last week despite Moscow warnings not to.

"We are making this brief stop to demonstrate US support for the important choice that Moldova made," said a senior US official who asked not to be named.

"We have been very clear with the Russians -- we do not see any reason to consider the decision by Georgia or Moldova as a zero-sum game" in which there can only be one winner, the European diplomat said.

"We think this type of manoeuvre is even counter-productive," the diplomat added.

As with Ukraine, Lavrov has been blunt on Georgia, charging that NATO was seeking ties with Tbilisi to promote division in a throwback to the Cold War.

NATO expansion "is a continuation of the old logic of the Cold War," he said. "It implies not only preserving the dividing lines, it's... moving these dividing lines further to the East."

"During this unsettled time, Ukrainian society has even more need of the EU's support," said Amanda Paul of the European Policy Centre and Vasil Filipchuk of the ICPS think-tank in Kiev.

"It is not enough just to criticise the excessive use of force," they said in a research note.

"The EU has to be visible at the highest possible levels."