The last 15 U.S. troops left Ecuador's Pacific Manta air base on Friday, officially closing the U.S. military post in what Ecuador's government calls a recovery of sovereignty.

The small U.S. mission flew anti-narcotics flights meant to help catch cocaine smugglers close to the point of production.

But Ecuador's leftist President Rafael Correa promised in his 2006 election campaign that he would not renew the U.S.' 10-year lease on the base. A new constitution approved in a referendum last year officially prohibited foreign military bases on Ecuadoran soil.

"The Ecuadorean government is very satisfied to comply with a constitutional mandate and deliver on a campaign promise ... by fully recuperating our sovereignty over the Manta base," Ecuadorean Security Minister Miguel Carvajal told the Associated Press.

The U.S. anti-narcotics force flew its last surveillance mission from the base in July. About 220 Americans occupied 5 percent of Manta's International airport since November 1999, but were allowed no more than eight planes at a time.

Martha Youth, spokeswoman for the U.S. Embassy in Quito, praised Ecuador's cooperation in anti-narcotics operations despite the closure of the base.

"We leave Manta conscious that these have been 10 very successful years. We've done good work in cooperation with the Ecuadorean authorities," Youth said.

Carvajal said Ecuador plans to continue cooperating with U.S. anti-narcotics efforts. "Relations with the U.S. remain very good, we have no problem in continuing to cooperate," he said.

U.S. plans to transfer the interdiction missions to bases leased in Colombia has sparked controversy across South America and saber-rattling by Venezuelan President Hugo Chavez, an ally of Correa.

During a ceremony marking the U.S. departure, Ecuadorean Foreign Minister Fander Falconi referred to Latin America as "the great motherland" and said the region "rejects all forms of supervision that attempt to bring about subordination."

Opposition assemblyman Cesar Montufar said the departure of U.S. troops is "worrisome, especially because of our proximity to Colombia and because drug trafficking could grow in our country."

The U.S.' E-3 AWACs and P-3 Orion surveillance planes based in Manta were credited with about 60 percent of drug interdiction in the eastern Pacific region.

Ecuador produces little coca — the base ingredient in cocaine — but is bordered by Colombia and Peru, the world's top cocaine producers.