Conservative and liberal lawmakers Wednesday sharply criticized President Obama's plan to start a U.S. troop withdrawal from Afghanistan in July 2011.

Washington (CNN) -- Conservative and liberal lawmakers Wednesday sharply criticized President Obama's plan to start a U.S. troop withdrawal from Afghanistan in July 2011.

Most Republicans backed the president's decision to send more troops. They claimed, however, he was playing politics by setting an "arbitrary" withdrawal deadline while insisting that any transfer of responsibility to the Afghan government ultimately will be based on conditions in that country.

They also argued he inadvertently strengthened the hand of Taliban and al Qaeda extremists by allowing them to know when a U.S. departure from the war-torn country would begin.

"I disagree with the president's decision to personally relay to our enemies when they can regroup and when they can retake Afghan territory," said Rep. Connie Mack, R-Florida and a member of the House Foreign Affairs Committee.

"I simply cannot understand and cannot agree with this approach," Mack said, adding that Obama's decision "emboldens our enemies [and] allows them to prepare and plan."

Announcing a firm date for starting an American withdrawal while also saying such a withdrawal depends on conditions in Afghanistan "are two incompatible statements," said Sen. John McCain of Arizona, the Senate Armed Services Committee's ranking Republican.

"You either have a winning strategy ... and then once it's succeeded, then we withdraw or, as the president said, we will have a date [for] beginning withdrawal in July 2011. Which is it? It's got to be one or the other. It's got to be the appropriate conditions, or it's got to be an arbitrary date. You can't have both."

"The president always has the freedom to adjust his decisions," Gates said, adding that Obama has made "a clear statement of his strong intent."