Ecuador has formally notified the US that it must vacate a base used to combat drug trafficking when the lease expires next year, the Foreign Ministry said on Wednesday.
Ecuadorian officials informed the US embassy of the plans, which have long been a pledge by President Rafael Correa despite objections from surrounding residents financially reliant on the Manta base.
The US and Ecuador signed a 10-year agreement in November 1999, which expires in August 2009, to establish the base in Manta for counter-narcotics operations. About 300 US soldiers are stationed there.
Ecuador is set to hold a referendum on a new constitution September 28 that does not allow for the presence of foreign bases in the country.
US State Department spokesman Sean McCormack told reporters in Washington the United States accepts Correa's decision but warned an absence of the base would leave a "serious gap" in efforts to intercept drug shipments.
"The decision to close the forward-operating location is a sovereign one by the government of Ecuador," McCormack said. "We note, however, that the closure will leave a serious gap in efforts by the United States and our partners to confront illegal drug trafficking throughout the region."
There has been speculation the US will ask another country to host a base. Among the countries named are Colombia or Panama. McCormack would not comment on alternative plans.