Anwar Ibrahim, the leader of Malaysia’s resurgent political opposition, took refuge on Sunday in the Turkish Embassy in the capital, Kuala Lumpur, saying he feared for his security after an aide accused him of participating in homosexual acts.
The police in Malaysia said they would investigate allegations by the aide, Saiful Bahari, a 23-year-old campaign worker, that he had been sodomized by Mr. Anwar. Sodomy is described under Malaysian law as “carnal intercourse against the order of nature” and is punishable by up to 20 years in jail.
The accusation, similar to one that led to Mr. Anwar’s dismissal as deputy prime minister and jailing a decade ago, comes at a time of turbulence in Malaysian politics, with Mr. Anwar threatening to woo enough defectors from the ruling coalition to form his own government.
Mr. Anwar spent six years in prison for the 1998 sodomy case but was ultimately acquitted and released.
“Not again,” said Mr. Anwar, reached by telephone inside the embassy. “It’s a repeat of the same script.”
In March, Mr. Anwar led opposition parties to their greatest gains in the country’s history, winning control of five states, including some of the largest and wealthiest in Malaysia. More recently Mr. Anwar had been preparing to announce plans for a by-election that would allow him to run for Parliament and ultimately be eligible to be prime minister, a post he has long desired.
He was barred from running in the March election because of a court order related to the 1998 sodomy case.
Mr. Anwar, who is friends with Turkey’s prime minister, Recep Tayyip Erdogan, said that he planned to stay in the embassy no more than a few days but that he feared that his political enemies wanted to do him harm.
“I want a guarantee from the government of my personal safety,” Mr. Anwar said. “I don’t have any intention of seeking political asylum or going overseas.”
Azizah Ismail, Mr. Anwar’s wife and a member of Parliament, called the allegation of sodomy “political murder.” At a news conference on Sunday in Kuala Lumpur, she showed a photo of the accuser with top officials of the governing party.
Abdullah Ahmad Badawi, the prime minister, denied any involvement in the new allegations.
He said his party “has no intention of wanting to make life difficult for him or to harass him.”
Mr. Abdullah’s party, the United Malays National Organization, in power since the country gained independence from Britain in 1957, is in turmoil following the March electoral losses. Mr. Abdullah has been under pressure to resign and has said he will soon hand over power to his deputy.
Ibrahim Suffian, the director of the Merdeka Center, an independent polling organization in Kuala Lumpur, said he believed the allegations would be met with “more cynicism this time.”
“From a political communications standpoint, I’m not sure all of this is going to help UMNO,” he said, referring to the governing party. Mr. Anwar, an ethnic Malay, may be seen as a victim of political persecution and garner sympathy among Malay voters, who form the core of the governing party’s support.
But if the allegations are proved true, Mr. Ibrahim said, it could greatly damage Mr. Anwar’s standing. “People tolerate homosexuality if it’s quiet,” he said. But Malaysians “have a heightened sense of morality” for the country’s leaders.
Mr. Anwar said he doubted his case would be treated with impartiality because senior officials in the police force and attorney general’s office are “very scared of any change of leadership.”
“The system is blatantly and manifestly corrupt,” Mr. Anwar said.
Malaysia’s police chief for criminal investigations, Bakri Zinin, said Mr. Saiful’s complaint accused Mr. Anwar of sodomizing him in a condominium in a Kuala Lumpur suburb.
Mr. Bakri said Mr. Anwar faced no immediate threat of arrest.
“We want to establish the allegation first to see whether there is truth or not,” he said at a news conference, according to The Associated Press. “We will conduct a thorough investigation and be fair to both sides.”