ROME (AFP) ― Top U.S. diplomat John Kerry met his Russian counterpart Sergei Lavrov on Sunday, amid anger in Moscow over the prospect of new U.S. sanctions and possible lethal military aid for Ukraine.

The meeting in Rome came after U.S. lawmakers passed a bill ― dubbed the Ukraine Freedom Support Act ― calling for additional sanctions against Russia and the delivery of up to $350 million worth of U.S. military hardware to Kiev.

“Undoubtedly, we will not be able to leave this without a response,” deputy foreign minister Sergei Ryabkov told Interfax news agency ahead of the talks.

The Senate bill must still be approved by the White House, which has so far been reluctant to provide direct military assistance to Ukraine for fear of being drawn into a proxy war with Russia, which is backing separatist forces in Ukraine. 

The legislation authorizes ― but does not legally require ― President Barack Obama to provide lethal and nonlethal military aid to Ukraine, including antitank weapons, ammunition and troop-operated surveillance drones.

State Department officials have insisted there are no plans to move beyond providing nonlethal supplies such as body armor and communications equipment.

U.S. officials have stressed the main thrust of Kerry’s pre-Christmas diplomatic whirl is a looming showdown at the U.N. on a bid for Palestinian statehood.

But the conflicts in Ukraine and Syria would also figure high on the agenda.

“We have a number of critical issues to talk about,” Kerry said, as he met with Lavrov in the splendor of the U.S. ambassador’s residence in Rome.

The talks between the two men went on for more than three hours, a senior State Department official said late on Sunday.

On Ukraine, the source said Kerry had “reiterated the importance of fully implementing the Minsk agreement and deescalating the situation on the ground.”

The Minsk agreement refers to a cease-fire deal agreed in the Belarus capital in September which has yet to be fully implemented.

In a flurry of meetings which will also take the top U.S. diplomat to Paris and London, Kerry was planning to discuss how to “remain in lockstep” with European allies and the “pressure strategy that we‘ve been using.”

The eight-month-old conflict between government forces and pro-Russian separatists in eastern Ukraine has left at least 4,634 dead and 10,243 wounded, and displaced more than 1.1 million people, according to new U.N. figures.

The threat of fresh sanctions comes as Russia’s economy crumbles under previous rounds of Western sanctions and a collapse in oil prices.

The Ukrainian army on Sunday reported 14 attacks on its positions in the past 24 hours, including one in which Grad rockets, mortars and antitank weapons were fired “as a provocation,” but no one was killed or wounded.

Ukraine has been worried for months that the Russia-backed separatists will launch an offensive on the port of Mariupol to carve a land corridor between the Russian border and the Crimean peninsula, a Ukrainian region annexed by Moscow in March.

Ukraine announced Friday it would bolster its army next year by conscripting another 40,000 soldiers, and doubling its military budget.

While the Russian economy has been hit hard by the conflict, the International Monetary Fund’s number two David Lipton said Saturday he was “impressed” by Ukraine’s plans for reform after lawmakers approved a government program of severe austerity cuts.

The IMF this year granted Kiev $17 billion in financial aid over two years, as part of a $27 billion global rescue package set up by Western countries.