KUALA LUMPUR — Malaysia's leader-in-waiting Anwar Ibrahim will be questioned by police over allegations he sexually assaulted a male former aide, officials said on Wednesday, the latest such scandal to tarnish his career.

Anwar has vehemently denied the claims by his former research assistant Muhammed Yusoff Rawther, who says he was assaulted last year.

The 72-year-old Anwar, seen as the likely successor to Prime Minister Mahathir Mohamad, spent almost a decade in jail after being convicted of sodomizing a young male aide, allegations that supporters say were aimed at ruining his political career.

Sex between men remains illegal under colonial-era laws in the Muslim-majority country.

He was released from prison and pardoned last year after his alliance stormed to a shock victory against a corruption-plagued coalition that had ruled the country since independence from Britain in 1957.

But political tensions have escalated sharply, with Anwar's nemesis-turned-ally Mahathir refusing to say exactly when he will hand over power, and vicious infighting erupting in his People's Justice Party (PKR).

The latest allegations emerged last week — just before the start of PKR's annual congress — with Yusoff claiming that Anwar assaulted him and attempted to force him to have sex, and lodging a police report.

The former aide was questioned this week over the allegations and police confirmed that Anwar had also been summoned, without saying when he too would be brought in for questioning.

Anwar said in a statement he was "prepared to assist the police probe as soon as possible", and dismissed the claims as "slander".

Anwar was first thrown in jail in the 1990s after being sacked from his position as deputy prime minister by Mahathir, who was in his first stint as premier at the time, and their stormy relationship has loomed over Malaysian politics ever since.

The pair reconciled ahead of last year's landmark elections in a bid to oust the scandal-mired Barisan Nasional (BN) coalition of Najib Razak.

But the new government has faced criticism for failing to move fast enough on reforms and improve the economy, and has lost a string of local elections. — AFP