US House Speaker John Boehner and a group of senior Republican and Democratic lawmakers are urging President Barack Obama to send “lethal” weapons to Ukraine.

“We urge you to quickly approve additional efforts to support Ukraine's efforts to defend its sovereign territory, including through the transfer of lethal, defensive weapons systems to the Ukrainian military," read a letter Thursday to the president by 11 lawmakers.

Boehner, House Majority Leader Kevin McCarthy, and top Republicans and Democrats from the House Foreign Affairs, Armed Services and Intelligence Committees, as well as the Republican chairs of the House Appropriations Committee and Defense and State and Foreign Operations Appropriations subcommittees all signed the letter.

The lawmakers described Russia's actions “a challenge to the West”. Washington accuses Moscow of arming and supporting pro-Russian forces fighting in Ukraine, however, the Kremlin calls the accusations "groundless."

Obama’s lack of “overall strategy thus far has done little to reassure our friends and allies in the region," they wrote in the letter.

Last month, the US president said Washington was still considering sending lethal aid to Ukraine, saying "If, in fact, diplomacy fails, what I've asked my team to do is to look at all options".

The letter was written after Boehner, other members of Congress and Ukrainian lawmakers met last week during which they discussed the need for additional US help to Ukraine.

In addition, Chairman of the Joint Chiefs of Staff General Martin Dempsey said Tuesday that the United States should consider providing lethal arms to Ukraine to help battle pro-Russian forces.

Meanwhile, the US and the European Union have agreed to "impose significant additional costs" on Russia if a ceasefire agreement about the Ukraine conflict is violated.

The decision was made Tuesday during a video conference between Obama and the leaders of Britain, France, Germany and Italy as well as the head of the European Council about the current situation in eastern Ukraine.

The leaders agreed to swiftly add further sanctions on Moscow if it does not stop pro-Russian forces in eastern Ukraine from breaching a two-week-old ceasefire.

AT/AT