The American Conservative Union is urging the Senate to reject a Ukraine aid package negotiated by the Foreign Relations Committee in favor of supporting a House-passed bill.

With the Democratic-controlled Senate set to resume consideration of legislation that would provide financial assistance to Ukraine and further sanction Russia, the ACU on Friday sent a letter to all senators outlining its opposition to the proposal because of an International Monetary Fund measure included in the bill. Passage of the bill was delayed last week because of a Republican filibuster.

“On behalf of the American Conservative Union, I urge you to oppose efforts to combine legislation extending a loan guarantee to Ukraine with increased funding for the International Monetary Fund along with changes to the funding structure that will be to the detriment of the United States. Instead, the Senate should pass the House bill and quickly send it to the president’s desk,” wrote Larry Hart, the ACU’s director of government relations.

President Obama's insistence on including IMF reforms in the bill has split Republicans.

The Republican-controlled House passed a measure similar to the Senate bill, but without the IMF provisions. Some Senate Republicans support the Senate bill despite their opposition to the part of the legislation dealing with the IMF, because they view the situation in Ukraine as too urgent to bog down U.S. aid and additional sanctions on Russia.

The ACU has not determined if it will include the vote on the existing Senate bill in its annual legislative scorecard.