Prime Minister Najib Abdul Razak has urged the authorities, in particular the intelligence units, to probe claims that the opposition had instigated the heir of the Sulu Sultanate to reclaim Sabah.

He said that this was a serious allegation and concrete evidence was needed to identify those behind the incident.

"There are photographs and circumstantial evidence but we need solid evidence to know who really is behind this," he said in Kangar, Perlis according to Star Online .

He said it was suspicious that the Sulu Sultanate had raised this issue just as the general election was approaching and would cooperate with Filipino authorities.

"All parties should (conduct) investigations. In the Philippines, President (Benigno) Aquino wants to know the truth as well.

"This is a major embarrassment to the Philippines government. They won't accept having their citizens intruding, terrorising, and using weapons to kill our people," said Najib.

Nur Misuari: Najib is kin

Over the past two days, Utusan Malaysia and TV3 have been accusing Anwar Ibrahim of having instigating the Sulu Sultanate, but he has denied the claims.

These claims were based on anonymous intelligence agency officials and the fact that Anwar had recently met former Moro National Liberation Front leader Nur Misuari.

However, Nur Misuari has been staunchly against the use of violence and have offered to mediate between Malaysia and the Sulu Sultanate.

According to a recent interview with Philippines' Davao Today , Nur Misuari had referred to Najib as his friend and a cousin of his grand nephew.

"So I intend to send him there, to talk to Najib and persuade him to desist from sending more forces (to Sabah).”