MANILA, Philippines -- The United States Embassy has clarified that American troops deployed in restive Mindanao are not stationed permanently in the Philippines and stay only at the invitation of the host country.

Asked to comment on the resurging debate on US military presence here, Embassy spokesperson Rebecca Thompson reiterated earlier statements that American soldiers were “never involved” in combat operations in the south amid the Philippines' campaign to rout rebel forces there.

“We don't have US forces permanently in the Philippines, so they come and go. They are here at the invitation of the Philippines. We have no bases or plans to base in the Philippines,” Thompson told the Philippine Daily Inquirer on Sunday.

The US military has been maintaining an undisclosed number of soldiers in Mindanao called the Joint Special Operations Task Force-Philippines (JSOTF-P), a unit from the Hawaii-based Special Operations Command-Pacific (Socpac), to provide advise and technical know-how to the Philippine military.

Socpac officials said in a briefing in their base in 2007 that JSOTF-P stayed away from combat operations as “a hard and fast rule” and “a clear policy,” and that all troop movements and activities were coordinated with the Armed Forces of the Philippines.

A Philippine Air Force top official in Mindanao said on Sunday that US aerial presence in the south was limited to transport aircraft providing lift to the American contingent in the area.

Maj. Gen. Hernanie Perez, commander of PAF's 3rd Air Division, said the US military maintained a modest fleet of transport planes in the Zamboanga air base for carriage of logistics and personnel.

“They only have medium lift aircraft for logistics and administrative flights... none for combat,” he said.

Perez said the US kept a small fleet of Bell-214 choppers, C-12 medium lift cargo planes and Beechcraft transporters at an expanded ramp of the PAF base there. He said he would see “six to eight planes” at one time.

“We have more because that [air base] is where we maintain our planes,” said Perez.

The US planes are parked at a ramp area extended several months back with the military's permission.

“The planes are at the end of the taxi way, at an extended ramp so that they won't take up space for our aircraft,” said Perez.

The Zamboanga base is one of four staging areas of PAF air strikes against rebel forces in the south and serves as maintenance hub for the military's air power.