Kuala Lumpur, May 12 (IANS): Former Malaysian Prime Minister Najib Razak, who was defeated in the general elections, has been banned from leaving the country, Immigration officials said on Saturday.

Najib said he and his wife Rosmah Mansor were planning to go on an overseas holiday following which the Immigration Department made the announcement via its social site account, BBC reported.

He gave no reasons for the authorities' decision but said he would abide by it. "I respect this instruction and will stay in the country with my family," he tweeted.

It is believed they intended to fly to Indonesian capital Jakarta.

Najib also announced that he was stepping down as the head of his United Malays National Organisation (UMNO) and the Barisan Nasional (BN) coalition following the poll defeat.

"As the President of UMNO and the Chairman of Barisan Nasional, I made the decision that I am stepping down as President and Chairman with immediate effect," he said at the UMNO headquarter in Kuala Lumpur.

In a historic election earlier this week, Najib's BN coalition, which had been in power since Malaysia's independence in 1957, lost to the Pakatan Harapan coalition led by Mahathir Mohamad, who took office as Prime Minister.

Najib has been accused of diverting $700 million from a state investment fund in 2015, a charge he denies. He has since been cleared by the authorities.

He had faced accusations of corruption and mismanagement over the state investment fund 1Malaysia Development Berhad (1MDB). 1MDB, set up by Najib in 2009, was meant to turn Kuala Lumpur into a financial hub and boost the economy through strategic investments.

But it started to attract negative attention in early 2015 after it missed payments for some of the $11 billion it owed to banks and bondholders.

After that, there were reports of around $700 million transferred from the fund to Najib's personal bank accounts.

The new government led by Mahathir vowed to re-open the investigation into the scandal of state investment fund 1MDB. Mahathir has said that if Najib were found to do something wrong, "he will have to face the consequences".