Kerry warns of 'additional' US assistance to Ukraine

US Secretary of State John Kerry gestures during a bilateral press conference with the Ukrainian Prime Minister in Kiev on February 5, 2015 (AFP Photo/Jim Watson) (Pool/AFP/File)

Washington (AFP) - The United States is weighing "additional" assistance to Ukraine as it battles Russian-backed separatists, Secretary of State John Kerry said Saturday, while stopping short of saying Washington would send arms.

Kerry's comments came as Western leaders challenged Russian President Vladimir Putin to prove he wants peace in Ukraine, warning both sides a new Franco-German peace drive may be a "last chance" to stop all-out war.

"I have no doubt that additional assistance of economic kind and other kinds will be going to Ukraine," Kerry said while attending a gathering of world leaders at the Munich Security Conference.

"And we do so understanding that there is no military solution. The solution is a political, diplomatic one," he told NBC's "Meet the Press" in an interview due to air in full Sunday.

While Western leaders were united in condemning Russia for supporting rebels at the conference, they differed on whether to back Ukraine's beleaguered army with weapons.

Momentum has built in Washington for giving Kiev high-tech military equipment, but German Chancellor Angela Merkel insisted such a step would only make matters worse.

The United States has so far provided non-lethal military equipment such as armored vests and helmets.

Putin, meanwhile, said Russia was not at war and does not want war with anyone, but lashed out at Western sanctions imposed as the Ukraine crisis has deepened.

"President Putin's got to make the decision to take an off-ramp," Kerry said in the interview.

"And we have to make it clear to him that we are absolutely committed to the sovereignty and integrity of Ukraine no matter what."

The Americans have insisted all sides must lay down arms as the first step towards any deal.