WASHINGTON (AP) – Sen. Hillary Rodham Clinton, a potential presidential candidate, on Wednesday called for capping the number of U.S. troops in Iraq and linking funds for Iraqi security forces to the government’s control of the violence-plagued nation.

Back from a weekend trip to Iraq and Afghanistan, the New York senator also called for increasing U.S. forces in Afghanistan, arguing more troops are necessary as Taliban forces are waiting to attack when weather permits.

Clinton was quick to seize the spotlight the day after Illinois Sen. Barack Obama took a major step toward entering the 2008 race. She made a round of appearances on network television and radio and participated in a Capitol Hill news conference.

Clinton said she would offer legislation that would not cut funding to U.S. troops, as some lawmakers want, but would, after a six-month time period, cut off money for Iraqi troops.

She said cutting off funds for security forces and private security contractors who guard many Iraqi leaders would show the U.S. government is serious about imposing “real world consequences” to failing to reduce the sectarian conflict killing tens of thousands civilians a year.

“I do not support cutting funding for American troops, but I do support cutting funding for Iraqi forces if the Iraqi government does not meet set conditions,” Clinton said, appearing at a news conference with the two lawmakers who traveled with her to Iraq and Afghanistan, Sen. Evan Bayh, D-Ind., and Rep. John McHugh, R-N.Y.

Clinton argued the Bush administration has failed to put any real pressure on Iraqi leaders at the same time the president is escalating the U.S. commitment there by sending 21,500 more troops.

“I think we will eventually have to move to tougher requirements on the administration to get their attention,” said Clinton, arguing that she wanted “a change of course, not adding more troops pursuing a strategy that under present circumstances, cannot be successful.”

More than 130,000 U.S. troops are in Iraq.

White House spokesman Tony Snow dismissed Clinton’s proposal.

“The idea of placing a cap on troops – what it does is something that no commander in chief would want to have, which is it binds the hands of the commander in chief and also the generals and frankly also the troops on the ground,” Snow said.

Clinton’s bill would, if Iraqis cannot show progress after six months, require Bush to get congressional authority for any additional troops in Iraq.

Even as she jousts with the White House, Clinton also is feeling heat from Democratic rivals, due largely to her position as the presumptive front-runner in a presidential race she has yet to enter.

On Wednesday, Obama called Iraq troop escalation “a terrible consequence of the decision to give him the broad, open-ended authority to wage this war in 2002,” an indirect shot at the voting record of Clinton and other Democrats.

Obama did say he favors a cap of U.S. troop levels in Iraq and the phased redeployment of troops, both of which Clinton support.

In a statement, Tom Mattzie of the liberal group MoveOn.org said they would like Clinton to “use her powers as a senator to stop the escalation and move toward a redeployment. A key test is how any senator puts words into action. We would welcome her future leadership.”

Clinton and Bayh sent a letter to Defense Secretary Robert Gates Wednesday calling for an increase in Afghanistan of two or possibly three infantry battalions, some 2,300 troops.

“Unlike in Iraq,” the senators wrote, “we have a government in Afghanistan committed to promoting national interests over sectarian ones, is making tangible progress in governance, sincerely wants more U.S. help, and is fighting the enemy that brought us Sept. 11.”