President Hugo Chavez says the US Navy jet which violated his country's airspace had been on a spying mission, he seeks US explanation.

"Three days ago an American warplane violated Venezuelan airspace and overflew a site which is forbidden to even civilian aircraft. We are sure they were spying," Chavez said in a speech broadcast on radio and television on Wednesday.

"We won't let ourselves be provoked, but we are also not going to allow our sovereignty to be violated. The North American empire and its lackeys have been told," he added.

The Pentagon later admitted that a US Navy surveillance jet had lost its way during a counter-drug mission and strayed into Venezuelan airspace.

Chavez denounced the violation of its airspace, and summonsed the US ambassador to explain the incident.