MANTA, Ecuador — Mayor Jorge Zambrano pulled up to the Manta City Hall in his black Ford Explorer, expecting to find a rally in support of the American military outpost that runs drug-surveillance flights from this gritty port city.

He left an hour later behind a wall of riot shields and a cloud of Mace as police fended off banner-waving protesters who crashed the event in March.

With 18 months left on its decadelong contract, the U.S. Forward Operating Location in Manta has few friends in this South American nation — and fewer still who believe the agreement has any hope of being extended.

Ecuadorean President Rafael Correa has vowed not to renew the base's contract beyond its November 2009 expiration. And politicians drafting a new constitution have proposed banning the base or any other foreign military presence in the country.

If the Manta base closes, it would leave the United States shopping for a new airstrip for the radar-mounted AWAC E3s and P-3 spy planes that ply the Eastern Pacific looking for drug runners.

It would also be another dark turn for rapidly deteriorating U.S.-Ecuadorean relations.

The United States sees the Manta compound — with its manicured lawns and staff of about 150 pilots and crew members — as part of a multinational effort that helped block $4.2 billion worth of narcotics last year.

But in Ecuador, the Base de Manta is viewed largely as an affront to national sovereignty that threatens to drag the country into the regional drug war.

The clashing views come as tensions between the nations are running high.

President Correa — a staunch ally of Venezuelan President Hugo Chávez — has made the ousting of the Manta base central to his presidency, and he recently led a shake-up of Ecuador's armed forces, alleging they were infiltrated by the CIA and too cozy with U.S. military advisers.

Colombia, a staunch U.S. ally, is accusing the Correa administration of sympathizing with the Revolutionary Armed Forces of Colombia, or FARC. Colombia claims a FARC laptop, seized during a controversial and bloody cross-border raid into Ecuador on March 1, revealed Correa's election campaign took FARC money.

Colombia also alleges María Augusta Calle — a member of Correa's Alianza País party who is pushing constitutional changes that would ban the Manta operation — allowed FARC to use her bank account.

Leaning back in his chair in a darkened briefing room, the commander of the Forward Operating Location in Manta, Lt. Col. Robert Leonard, admits the United States is losing the public-relations battle.

"There is so much misconception out there as to what we do here and what's going on," he said. "And as you get further away from Manta, those misconceptions grow."

Soon after the Colombian incursion, which killed 25 people, including FARC leader Raúl Reyes and an Ecuadorean national, rumors swirled in Ecuador's press that it was spy planes from Manta that helped pinpoint the rebel camp — and may have even carried the bombs for the strike.

The United States insists the stories are fiction, and analysts point out Colombia has little need for such help. But the rumors have found a receptive audience in Ecuador, and the government has called for an audit of Manta's operations.

What it will find, Leonard says, are a handful of unarmed aircraft, dedicated solely to looking for drug runners at sea and in the air.

The base is one of three in the region — including El Salvador and Aruba-Curaçao — that feed information to the Joint Interagency Task Force in Key West. JIATF South, as it's known, consists of different U.S. agencies and liaison officers from 12 nations, including Ecuador.