By Manuel Mogato

MANILA (Reuters) - President Rodrigo Duterte on Monday called for the withdrawal of U.S. special forces troops from a group of islands in the southern Philippines, saying their presence could complicate offensives against Islamist militants notorious for beheading Westerners.

Duterte, who was in the spotlight last week over a televised tirade against the United States and President Barack Obama, said the Americans still in Mindanao were high-value targets for the Islamic State-linked Abu Sayyaf militants as counter-insurgency operations intensify.

"They have to go," Duterte said in a speech during an oath-taking ceremony for new officials. "I do not want a rift with America. But they have to go."

He added: "Americans, they will really kill them, they will try to kidnap them to get ransom."

The comments by Duterte, a former southern mayor known for his terse words and volatile temperament, add to uncertainty about what impact his rise to the presidency this year will have on one of Washington's most important alliances in Asia.

A spokesman for the U.S. State Department, John Kirby, said it was not aware of any official communication by Manila calling for a withdrawal. He said Washington remained committed to the alliance.

Another U.S. official said there were only a "handful" of special forces in the Mindanao acting in limited liaison roles.

White House spokesman Josh Earnest emphasized shared concerns and interests with the Philippines, before taking a thinly veiled swipe at Duterte, appearing to compare him to Donald Trump, the outspoken Republican candidate in the Nov. 8 U.S. presidential election.

"I think it’s an indication of how important elections are," Earnest told a regular news briefing.“Elections have consequences. Elections do say a lot about what kind of person is going to represent your country on the international stage.

"And it’s why you are going to prize qualities like decorum and temperament and judgment in casting votes in elections, because you know that person is going to represent you on the international stage. That’s certainly something that the Filipino people are well aware of."

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Obama canceled a planned meeting with Duterte at last week's ASEAN summit after Duterte appeared to call him a "son of a bitch". The two did eventually meet briefly and on Friday Duterte said he told Obama the remark was not directed against him.

Washington deployed special forces soldiers to Mindanao in 2002 to train and advise Philippine units fighting Abu Sayyaf militants in a program that once involved 1,200 Americans.

It was discontinued in 2015 but a small presence has remained for logistics and technical support.

Washington has since shifted much of its security focus in the Philippines toward the South China Sea, where the two countries have shared concerns about China's territorial claims.

As a counter to China, shortly before Duterte came to office, Washington and Manila enacted the Enhanced Defense Cooperation Agreement giving the United States rotational access to five bases in the Philippines.

Commander Gary Ross, a Pentagon spokesman, said on Monday that it would "consult closely with our Filipino partners to appropriately tailor our assistance to whatever approach the new administration adopts" on counter-terrorism measures.

(Additional reporting by Lesley Wroughton, David Brunnstrom, Phil Stewart, Ayesha Rascoe, Idrees Ali in Washington; Editing by Martin Petty and Grant McCool)