Baghdad, Iraq ? Supporters of anti-American cleric Muqtada al-Sadr said Thursday that they’d gathered enough support in Iraq’s parliament to pass a bill requiring a timetable for U.S. forces to pull out.

The legal or practical implications of an Iraqi law that would attempt to require a timetable for U.S. troops to leave the country were unclear. Even those circulating the legislation said they expected to sort out particulars in parliamentary debate.

But the announcement, on the anniversary of the parliament’s swearing-in last year, underscores the difficulty of the American position in Iraq.

Parliament has been unable to reach a consensus on key issues that U.S. officials say are crucial to resolving Iraq’s sectarian violence, including measures dividing oil revenues and permitting some former members of Saddam Hussein’s Baath party to have government jobs.

Al-Sadr supporters, however, said that this week they finished collecting 144 signatures – a majority of the 275-member legislature – on a bill demanding a scheduled withdrawal and an immediate freeze on the number of foreign soldiers in Iraq. A similar effort last year drew only 113 signatures, said one Sadrist member of parliament, Salagh Augali.

The bill doesn’t spell out what the timetable should be, but backers said their support drew on Sunni Muslim Arab, Shiite Muslim, Kurdish and secular factions in parliament. Augali said its passage would be more than a symbolic act.

“This will make a difference,” he said.

In Washington, White House officials reacted skeptically. “The prime minister, the president and the vice presidents of Iraq have made it clear that they think U.S. troops are needed in Iraq,” said Gordon Johndroe, a spokesman for the National Security Council. “We’ve heard these claims before (from al-Sadr supporters), but they rarely materialize.”

It’s unclear whether the measure would become law without further approval from Iraq’s president or prime minister.

President Bush has fought similar efforts in Congress to impose a timetable for a U.S. withdrawal.

Last week, he vetoed legislation that would have required American forces to begin leaving Iraq later this year, and has said he’ll veto any effort to impose such deadlines. The House of Representatives on Thursday passed legislation that would pay for military operations through September and tie future money to Iraqi approval by mid-July of laws governing oil revenues, de-Baathification and constitutional reform.

Word of the Iraqi pullout legislation came amid growing signs of dissatisfaction in parliament over the inability of Prime Minister Nouri al-Maliki’s government and U.S. officials to curb violence in neighboring Diyala province.