Free trade talks between the United States and South Korea are coming down to the wire Friday, with the presidents of both countries urging negotiators to reach an agreement.

The talks must be wrapped up by Saturday morning for the agreement to benefit from President Bush's special authority to submit trade agreements to Congress without amendments.

Several main sticking points remain, including access to markets for automobiles and agricultural products.

South Korean officials say U.S. President Bush and President Roh Moo-hyun spoke by phone Thursday and agreed to urge negotiators in Seoul to use maximum flexibility in reaching an agreement.

Supporters of a free trade agreement say cutting tariffs and other barriers could boost annual trade between the two nations by 20 percent. It is currently about $75 billion.

Opponents of the deal clashed with riot police today in Seoul outside the presidential residence. Some argue that the deal could eliminate many jobs.