Progress on Smuggled Chinese Seen : Immigration: U.S. officials are working on an agreement in which Mexico would be paid to repatriate 659 people on ships off the Baja coast.

SAN DIEGO —  Hundreds of increasingly restless Chinese immigrants remained in Coast Guard custody aboard three idle ships near Ensenada on Saturday, adrift in a flurry of negotiations between the United States and Mexico.

But there was apparent progress Saturday toward agreement on a U.S. request that Mexico detain and repatriate the 659 immigrants waiting on the smuggling vessels that were intercepted last week, U.S. officials said.

Although Mexico had issued a statement rejecting the proposal Friday, a State Department spokeswoman said Saturday that diplomats were still negotiating in Mexico City. The United States has offered to compensate Mexico for the costs of flying the immigrants back to China.

“They are still talking,” spokeswoman Phyllis Young said. “That’s very encouraging.”

In the meantime, transporting the immigrants to Ensenada remains one of several options for which the Coast Guard is preparing, Capt. Richard Clark said.

And in anticipation that Mexico will formally agree to cooperate, a U.S. government official said, U.S. Immigration and Naturalization Service officers who speak Chinese languages are being assembled to help screen the passengers at the request of Mexican authorities.

The spokesmen for the Mexican foreign relations and interior ministries could not be reached for comment Saturday. The statement they issued Friday seemed to leave room for negotiation, expressing Mexico’s willingness to apprehend the immigrants and even return them to China if they entered Mexican territorial waters. In Mexico, the political asylum process is speedier than in the United States.

The latest episode in the illegal influx of Chinese began a week ago when the Coast Guard detected the three smuggling vessels steaming toward Baja California, testing the Clinton Administration’s announced crackdown against seaborne smuggling.

On Saturday U.S. officials cast doubt on a report by Mexico’s director of migratory services that the Mexican navy had detected four additional smuggling ships near Baja.

Despite aggressive aerial and ship surveillance, the Coast Guard has not been able to detect additional smuggling vessels, nor has it received any request from the Mexican navy for assistance or intelligence information, said Chief Warrant Officer John Hollis.

“We cannot confirm that there are any other vessels,” Hollis said.

The ships waiting 60 miles west of Ensenada were transformed into floating detention centers, with Coast Guard personnel playing the delicate role of benevolent jailers. The Coast Guard supplied the immigrants with 350 pounds of rice and 3 pallets of military rations Saturday, Hollis said.

The Chinese immigrants have grown tense and bored since the smuggling vessels were intercepted four days ago, Hollis said, but there have been no significant problems.

“They are just sitting around,” he said. “They would like to be going somewhere. They know that things are out of their control. They are not happy, but there’s no armed revolt. . . . There has been some grumbling and stuff, but nothing major.”

Each armed Coast Guard boarding party consists of about 20 officers and crewmen; the three vessels have 254, 236 and 169 passengers aboard, respectively.

The potential for trouble has disturbing precedent. In incidents from Mexicali to Honduras to New York, desperate Chinese immigrants have variously attempted suicide, escape and mutiny when faced with return to their homeland. Even a U.S. official who asked not to be identified questioned the wisdom of detaining the group at sea for days on end.

“It’s bordering on inhumane treatment,” he said.

The Clinton Administration’s request for Mexico’s assistance comes as the President is stepping up efforts to keep the immigrants from entering U.S. territory.

Chinese immigrants often request political asylum, forcing authorities to either pay incarceration costs or release them pending hearings. Many applicants, who are economic refugees trying to manipulate a backlogged asylum process, never report for hearings, according to officials.