Turkey has stopped all traffic crossing its southern border with Iraq amid growing expectations of a US-led war with Saddam Hussein.
Oil transportations have been stopped
The transportation of goods from Turkey to Iraq has been halted and oil tankers within Iraq have been told to return to Turkey.
The move came amid expectations that the Turkish parliament would on Thursday vote whether to allow US troops onto Turkish soil for a possible northern invasion of Iraq.
"If nothing out of the ordinary happens, the motion will be
discussed in the assembly tomorrow," Tayyip Erdogan, leader of the
ruling Justice and Development Party (AKP), told the CNN Turk
With momentum towards war gathering pace, the Turkish Government said it was closing its embassy in Baghdad, while Nato equipment has started to arrive in the south-east of the country.
As the only Nato member to share a border with Iraq, Turkey is a key strategic ally for America and as such has been under immense pressure from Washington to assist its troops.
Turkey imports around 10% of its oil from its southern neighbour - almost every day thousands of oil tankers cross the Habur Gate, Turkey's land-link to Iraq.
The BBC's Jonny Dymond in Ankara says it looks very much as if Turkey is preparing to become a front-line state.
He says that while parliament - like the Turkish people - is hostile to war, it is thought likely that it will approve the deployment of US troops when it votes.
Mr Erdogan convened a meeting of party deputies on Wednesday to try to persuade them to support the measure.
Parliament has delayed debating the motion while US and Turkish officials negotiated a multi-billion-dollar deal on aid from Washington and the role Turkish troops might play in northern Iraq.
Turkish Economy Minister Ali Babacan said discussions were continuing over a US offer of $6bn in grants and an $8.5bn bridging loan.
The motion also authorises Turkish troops to enter Iraq.
Turkey's own military build-up is continuing
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 fears that events in northern Iraq could have a knock-on effect on its own Kurdish territories.
Several hundred US military vehicles have been unloaded at the Mediterranean port of Iskenderun, in south-east Turkey, in the last few days.
And several US ships laden with troops and equipment are still waiting off the coast for clearance to land.
Nato has also begun to deliver military equipment requested by Turkey to bolster its defences.
Three Patriot missile batteries have arrived at Iskenderun from the Netherlands, and two Awacs radar surveillance planes have been sent from Germany.