By Kim Ghattas
BBC correspondent on the Syrian border
As the countdown to war continues, Iraqis have been trying to get out of the country.
But since midday on Tuesday, they have been unable to cross the border into Syria.
Many Iraqis are trying to flee Baghdad before war begins
There were conflicting explanations about why this was the case, but from speaking with Iraqis waiting to be let in and officials on both sides it appears that Syria decided to close its border after an influx of Iraqis earlier in the morning.
The Iraqi side then decided not to process any more passports for travelling Iraqis.
An Iraqi custom official expressed his anger at the Syrian decision, saying it was turning back families with women and children at a time when their lives were at risk because of an impending war.
A few Iraqis did make it to the Syrian side, where custom officials checked all passports thoroughly and asked travellers where they were going and why.
One Syrian border official said they were only allowing in Iraqis who were travelling on their own.
Big groups or families had to be turned back, he said, because it was obvious they were trying to flee.
Many Iraqi taxis and buses and their passengers are now finding themselves stranded on the border with not enough petrol to drive back to Baghdad.
The four-hour drive from the Iraqi capital to Syria requires that cars fill up with petrol just before or just after they leave Iraq.
On the road between Baghdad and the border, however, there were long queues at the few open petrol stations, and cars were not being allowed to fill up completely.