DAMASCUS, Oct 1 Syria reimposed rules barring entry to Iraqi refugees on Monday, the United Nations refugee agency said.
"The borders are once again closed (to refugees)," said a spokeswoman for the United Nations High Commissioner for Refugees. "The UNHCR will urge Syria to grant humanitarian visas."
Jordan, the other main escape route for Iraqi refugees, imposed visas a few years ago but Syria had granted Iraqis a three-month permit to stay at the border.
Last month Damascus introduced tougher regulations, citing pressure on its infrastructure and public services, but lifted them a few days later as a temporary gesture for the start of the fasting month of Ramadan.
Under the new scheme, only Iraqi merchants, businessmen and university professors with visas obtained from Syrian embassies may enter Syria.
Syria has taken in an estimated 1.4 million to 2 million Iraqi refugees since the 2003 U.S.-led invasion of Iraq, with 4,000-6,000 refugees entering daily across the desert border.
Iraqi Vice President Adel Abdel Mahdi, in Damascus last week, urged Syria to provide better services for the refugees and give them residency in large numbers.
Mahdi did not say whether he had asked the Syrian government to abandon the visa scheme to stop the refugee influx.
"The two countries agree that any Iraqi who wants to go to Syria from now on must have a visa first," an Iraqi official told Reuters.