The Turkish Government has handed parliament a motion to permit 62,000 US troops to be deployed in Turkey for six months.
Thousands of US troops are waiting offshore
The motion, which would enable US forces to use Turkey as a springboard for an attack on Iraq, had been scheduled for debate on Tuesday, but one report suggested it may not now be put to a vote until Thursday.
US and Turkish officials negotiated through Monday night on a multi-billion-dollar aid package from Washington, and the role Turkish troops might play in northern Iraq, but some details remained unresolved.
US TURKISH PLANS
The Turkish cabinet finally agreed to the US deployment request on Monday after weeks of mounting pressure from Washington, which wants the option of a northern front in any war against Iraq.
The BBC Turkey correspondent, Jonny Dymond, says parliament is hostile to the idea of war, and that MPs do not want to vote until a satisfactory deal with the US has been agreed.
There is also widespread public opposition.
However, when the vote does take place, parliament is expected to approve the deployment.
The AK Party has a huge majority, and it would take a very big rebellion to block the deployment.
To have kept the process any longer would not have been very healthy, therefore it was
decided to send the authorisation to parliament today
deputy prime minister
Deputy Prime Minister Ertugrul Yalcinbayir said he would join the rebels.
"In my opinion there is no legitimate ground (for war). If the motion is not passed, there will be more unity, more peace and more democracy in Turkey," he said.
The motion also authorises Turkish troops to enter Iraq.
It is thought that tens of thousands of Turkish soldiers might be given a military role by the US in securing Kurdish northern Iraq.
Turkey has been bargaining with the US for weeks on a multi-billion-dollar compensation package in return for agreeing to the deployment.
Turkey's own military build-up is continuing
The government in Ankara also wants assurances about border security and the political structure of Iraq after any war.
The issue is a sensitive one for Turkey, which fears that events in Kurdish northern Iraq could have a knock-on effect on its own Kurdish territories.
But Turkey, as the only Nato member to share a border with Iraq, occupies a key strategic position - hence the heavy US pressure to agree to the deployment.
In a further complication, the Turkish president declared last week that no deployment could go ahead without a second UN resolution.
He must approve the deployment, and it is not clear whether he might try to block it.
Once approved, the US deployment would begin without delay.
US ships laden with troops and equipment are waiting off the coast for clearance to land.