Prime Minister Najib Abdul Razak purportedly revealed that BN spent RM1.5 billion for the 13th general election in a meeting with Umno liaison chiefs, according to former Kedah menteri besar Mukhriz Mahathir.

Mukhriz claimed that he was told about this after quizzing Najib in the meeting about the RM2.6 billion that was deposited into the latter's personal bank accounts, which the prime minister stated was a political donation from the Middle East.

Therefore, Mukhriz questioned how Najib could return RM2.03 billion of the RM2.6 billion if RM1.5 billion was spent on the election.

"What I find strange and curious about the RM2.6 billion which he claimed was an Arab donation is, if having spent RM1.5 billion in the 13th general election, only RM1.1 billion is left.

"How can he return RM2.03 billion to the Arabs? How did the (remainder of) RM1.1 billion become RM2 billion?

"I think even children can understand that the figures don't add up," he said, according to a video uploaded by blogger Din Turtle on Youtube .

Mukhriz, who is the son of former premier Dr Mahathir Mohamad, was speaking to Umno grassroots members in a function in Kelantan on Monday.

Recounting the meeting with Najib, Mukhriz said he had questioned the prime minister but was interrupted by Umno secretary-general Tengku Adnan Tengku Mansor, who is also referred to as Ku Nan.

"Ku Nan interrupted, the president did not answer, he (Tengku Adnan) said: 'We spent a lot for the 13th general election. We had to spend a lot to make sure we win' but he said he cannot reveal how much was spent.

"Then suddenly the (Umno) president (Najib) interjected, he said he can reveal how much was spent in the 13th general election. He said we spent RM1.5 billion," said Mukhriz.

The former MB said he was shocked and questioned how BN could perform even worse than the previous general election despite spending such a huge sum

"Then Ku Nan replied: 'you're still young, what do you know'," said Mukhriz.

Mukhriz said he rebutted Tengku Adnan by stating it was this "young person" who had helped BN improve its performance in Kedah and recapture the state in the general election but the same cannot be said at the national level.

"Thinking back... at RM1.5 billion, where did the money go?

"It didn't seem like we spent that much. The results was not satisfactory.

"In the past, we didn't even need to spend that kind of money and we could win two-thirds majority (in Parliament)," he added.

The RM2.6 billion was said to be a political donation from the Saudi royal family ahead of the last general election.

Attorney-general Mohamed Apandi Ali, in clearing the prime minister of any wrongdoing, said that RM2.03 billion was later returned to the donor.