PETALING JAYA • Former premier Mahathir Mohamad has asked Deputy Prime Minister Ahmad Zahid Hamidi to show proof that the US$700 million (S$980 million) moved into Prime Minister Najib Razak's personal bank accounts is a donation from an Arab man as claimed.

"The new Deputy Prime Minister says he has seen the Arab who gave the money. Then let him give proof that this Arab has huge sums of money to give away to Malaysia and many other countries," said Tun Dr Mahathir in his blog yesterday .

"Which countries? What is the source of this money? What business does he do? What is the name of the bank he uses?" the former premier questioned.

The information, he said, could have been verified by a task force formed to probe the flow of money allegedly through entities linked to the loss-making state investment arm 1Malaysia Development Berhad (1MDB). But the task force was disbanded early this month.

1MDB, whose advisory board is headed by Datuk Seri Najib, has been dogged by accusations of graft.