EAGLE PASS, Texas (AP) _ An opposition party leader said Wednesday he will give up his fight to be mayor of Piedras Negras if it is the only way to end the unrest that has plagued the border city since December.

Dr. Eleazar Cobos, the defeated mayoral candidate of Mexico's opposition National Action Party, said he will return later this week to Piedras Negras, Mexico, where more than 100 people fled a violent political rally last weekend.

Cobos, who claimed victory in Piedras Negras' Dec. 2 elections, said he will abide by the wishes of party leaders if they want him to give up his bid.

''It's possible that it's the only solution. I will do whatever the leaders ask. If they ask me to withdraw, I will do so,'' Cobos said in a telephone interview.

Cobos claims he won the December elections by more than 400 votes. But the candidate for the governing Institutional Revolutionary Party also claimed a narrow victory and the PRI-controlled electoral commission declared Carlos Juaristi Septien the winner.

Cobos and his supporters have refused to concede defeat, insisting they have documentation to prove PAN's victory.

On Sunday, about 2,000 people demonstrated in Piedras Negras to protest the elections and blocked access points to the international bridge into Eagle Pass.Chaos and rock-throwing erupted when police converged on the demonstrators and started shooting, witnesses said.

More than 100 people fled across the bridge and sought refuge in this Texas border city. All but 17 were returned to their homes Monday. The 17 have asked for temporary refuge until calm is restored.

''I didn't come to flee the violence or to seek political asylum,'' Cobos said. ''The reason I came was to bring my children to school. They attend school in Eagle Pass. And to rest.''

One woman shot during the melee was hospitalized in Eagle Pass with a bullet wound in her leg, hospital officials said. Mexican police also said three officers were shot during the violence, U.S. officials said.

U.S. Immigration Inspector C.E. Cunningham said one Mexican newspaper, the ''Vanguardia,'' reported that Mexican authorities had begun the legal paperwork to have one of the 17 extradicted to Mexico to face charges in connection with the shooting of the three officers.

Cobos said he has called for restraint and an end to the violence.

He said PAN leaders were in Mexico City hoping to meet with President Miguel de la Madrid in hopes of finding a solution to the problem.

The ruling PRI party has won virtually all major elections since its founding 55 years ago. The opposition, however, has gained strength, winning a number of smaller elections in areas near Piedras Negras.

The protest Sunday followed one on Dec. 29 that also turned violent, resulting in at least one death, a number of injuries and the burning of the Piedras Negras city hall.