House Speaker John Boehner and a bipartisan group of senior Congressional figures have written to President Obama, urging him to provide “lethal defensive weapons” to Ukraine in order to help the country defend itself from pro-Russian rebels.

“In the wake of a cease-fire agreement that appears only to have consolidated Russian and separatist gains since the first Minsk agreement, 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,” the letter says.

The document also cites Ukrainian President Petro Poroshenko's call, during a Sep. 18, 2014, address to Congress, for the U.S. and Western countries to “put action behind their commitment to freedom.” It urges Obama to make use of the powers Congress voted him to provide lethal military assistance to aid Ukraine, as Poroshenko requested.

“The Congress responded to [Poroshenko's] call to action. We sent you the Ukraine Freedom Support Act in December. To date, the administration has not utilized the authorities provided [by the act] to provide defensive military systems to the Ukrainian government.

Obama signed the Ukraine Freedom Support Act on Dec. 18, but noted in a statement that day that “the administration does not intend to impose sanctions under this law, but the act gives the administration additional authorities that could be utilized, if circumstances warranted,” ABC News reported.

The letter also reveals that Ukrainian lawmakers visiting Washington this week conducted meetings with Pentagon officials at which a “list of military equipment,” was discussed.

“In the face of Russian aggression, the lack of clarity on our overall strategy thus far has done little to reassure our friends and allies in the region who, understandably, feel vulnerable. This needs to change.”

The letter was signed by Boehner; House Majority Leader Kevin McCarthy, R-Calif.; Appropriations Committee Chairman Hal Rogers, R-Ky.; Armed Services Committee Chairman Mac Thornberry, R-Texas; Foreign Affairs Committee Chairman Ed Royce, R-Calif.; Intelligence Committee Chairman Devin Nunes, R-Calif.; Defense Appropriations Subcommittee Chairman Rodney Frelinghuysen R-N.J.; State and Foreign Operations Appropriations Subcommittee Chairwoman Kay Granger, R-Texas; Rep. Eliot Engel, D-New York, the ranking member of the House Foreign Affairs Committee; Rep. Adam Schiff, D-Calif., the ranking member of the House Permanent Select Committee on Intelligence; and Rep. Adam Smith, D-Wash., the ranking member of the House Armed Services Committee.