BAGHDAD (Reuters) -- A landmark pact to allow U.S. troops to stay in Iraq until 2011 has hit its first major political snag, with Iraq's ruling Shi'ite parties calling for changes just days after a "final draft" was unveiled.
The draft of the pact was agreed last week after months of difficult negotiations between Baghdad and Washington, and Iraqi officials had previously described it as a final text unlikely to be renegotiated.
But the Shi'ite alliance, which includes Prime Minister Nuri al-Maliki's Al-Da'wah Party, said its leaders had reviewed the pact at a meeting on October 18 and were not happy with all of it.
"Beside the positive points that were included in this pact, there are other points that need more time, more discussion, more dialogue and amendments to some articles," the alliance said in a statement.
It did not say what parts of the text gave rise to objections, but said a committee would gather comments on it.
The reservations voiced by al-Maliki's own alliance are a blow to the prospects of the pact, which needs to be approved in parliament by the end of this year when a UN Security Council resolution authorizing the U.S. mission expires.
Iraqi leaders say they could seek an emergency extension of the U.N. mandate if a bilateral deal is not ready in time.
The call by the Shi'ite parties for changes to the draft appears to contradict Foreign Minister Hoshyar Zebari, a Kurd, who said on October 18 that Washington and Baghdad consider the draft final and would be unlikely to reopen it.
Zebari said Iraq's parliament would be sent the draft to approve or reject but would not be permitted to make changes.
Enacting the pact would mean that, for the first time, U.S. troops in Iraq carry a mandate from Iraq's elected government, seen as a major step on the road to full sovereignty for Iraq.
But giving their formal blessing to the U.S. mission is a politically difficult step for Iraq's government when many Iraqis consider the U.S. presence an occupation and say they fear Washington wants a permanent foothold in the country.
The draft requires U.S. troops to leave Iraq at the end of 2011 unless Baghdad asks them to stay. It also provides certain conditions under which U.S. troops might be tried in Iraqi courts for serious crimes committed while off duty, which Iraqi officials have described as a major concession from Washington.
U.S. officials still have yet to comment on the contents of the draft in public, but briefed members of Congress -- including presidential candidates Barack Obama and John McCain -- about it on October 17.
"When the agreement is finalized, and both sides agree that that is the final language, it will be an open and transparent document so that the citizens both of Iraq and the United States can understand what is in it," U.S. military spokesman Rear Admiral Patrick Driscoll said on October 19.
The Shi'ite alliance includes al-Maliki's Al-Da'wah Party and its powerful rival, the Islamic Supreme Council of Iraq, which jointly contested the 2005 elections that brought al-Maliki to power but maintain separate blocs in parliament.
Another big Shi'ite group, followers of cleric Muqtada al-Sadr, opposes the pact and brought thousands of demonstrators into the streets of Baghdad on October 18 to march against it.