Updated: 10:50 a.m.

Senate Republicans informed Majority Leader Harry Reid (D-Nev.) in a letter signed by all members of the minority Conference that they will block all legislation during the lame-duck session until the chamber has acted to fund the government and extend Bush-era tax cuts for all income tax brackets.

The current income tax rates, established in 2001 and 2003 under President George W. Bush, are set to expire on Dec. 31 and revert to their previous, higher levels unless Congress acts. Funding to keep the federal government operational is set to dry up Friday. In the letter to Reid, dated Monday, Senate Republicans say bluntly that they will block everything until those two issues are addressed.

“We write to inform you that we will not agree to invoke cloture on the motion to proceed to any legislative item until the Senate has acted to fund the government and we have prevented the tax increase that is currently awaiting all American taxpayers,” Senate Republicans write. “With little time left in this Congressional session, legislative scheduling should be focused on these critical priorities.”

On the Senate floor Wednesday morning, Reid blasted Republicans for sending the letter, noting it was released the same day that Sens. Max Baucus (D-Mont.) and Jon Kyl (R-Ariz.) are meeting with White House officials to discuss how to extend the Bush-era tax cuts.

Republicans “know that the true effect of this letter is to prevent the Senate from acting on many important issues that have bipartisan support,” Reid said. The letter “simply puts in writing the political strategy that the Republicans pursued this entire Congress, namely obstruct, delay,”  he said.

Minority Leader Mitch McConnell (R-Ky.) retorted that “it’s time to get serious” about fiscal matters instead of other legislative items such as immigration reform.

“We need to show the American people that we care more about them and their ability to pay their bills than we do about the special interest groups’ legislative Christmas list,” McConnell said.

Senate Democrats, fresh off approving an overhaul of food safety regulations, are intending to move on to an immigration measure and a repeal of the ban on gays and lesbians serving openly in the military. President Barack Obama has also been pushing the Senate to approve the new Strategic Arms Reduction Treaty with Russia before adjourning for the year.