Prime Minister Najib Abdul Razak wasted no time hitting back at his critics upon his arrival in Kuala Lumpur tonight, aiming his shots mainly at his predecessor Dr Mahathir Mohamad.

"I want to tell you, when he was prime minister, he wanted to see President (George W) Bush.

"I want to tell you tonight that he paid lobbyists millions of ringgit," Najib told a thousand-strong crowd that greeted him at the Bunga Raya Complex near KLIA tonight.

The supporters came with banners and placards bearing messages, among others, "Welcome home, PM", "Live and die with PM Razak", "We're Geng Najib Razak" and "We love PM".

Using a mocking tone, Najib went on to say: "Millions were paid, why? Because he wanted to see Bush.

"But Mahathir did not get the same welcome as me," Najib added.

Mahathir yesterday mocked at Najib's meeting with US President Donald Trump, saying the prime minister used his announcement of some US$20 billion in investments in the US to buy Trump's support.

Najib claimed that Mahathir had approached Hong Kong-based lobbyist Ken Schiffer to set up his meeting with Bush.

"Mahathir used the late Megat Junid as his main planner.

"And how did he pay? Using TNB coal contracts," the prime minister said.

He said Deputy Prime Minister Ahmad Zahid Hamidi, who was present, could confirm the facts.

Najib added that if need be, more would be exposed on the matter.

Mahathir had met with Bush in 2002 and had for years been accused of paying for the meeting.

The Washington Post reported that Mahathir had allegedly hired Washington lobbyists through the US-based Heritage Foundation to persuade the White House to agree to the meeting.

The report claimed that the expenditure for the lobby activities amounted to about RM5.3 million.

Meanwhile, the Los Angeles Times claimed the Mahathir government had paid a Republican lobbyist US$1.2 million to set up his meeting with Bush.