US President George W. Bush and French President Nicolas Sarkozy had "fierce" arguments at last year's Group of Eight summit, Japan's then premier Shinzo Abe said Sunday.

Abe offered the tidbit from last year's closed-door session as a lesson for Japan not to be too reserved about steering discussions as it hosts this year's G8 summit in the northern mountain resort of Toyako.

Last year's G8 summit in Germany saw "pretty fierce" discussions, particularly over climate change, Abe told the private Asahi network.

"In particular, President Bush and President Sarkozy had a fierce dispute," Abe said.

"President Sarkozy was making his argument in a very strong way," in part because it was his first summit and he faced elections, Abe said.

Asked if Sarkozy threatened to Bush to walk out of the summit, Abe said with a smile: "He said something close to that."

Sarkozy has been known as more pro-American than his predecessor Jacques Chirac, who had a bitter feud with Bush over the Iraq invasion, although the French leader has also called on Bush to take tougher action on climate change.

German Chancellor Angela Merkel, last year's host, brokered a hard-fought deal for the G8 powers to agree to "consider seriously" at least halving carbon emissions blamed for global warming by 2050.

"Summit talks never go along the scenario set in advance. Many world leaders have strong characters and talk about their views and national interests eloquently," Abe said.

Abe, who picked the venue of the G8 summit, was speaking from his home in western Japan. He last week met his successor Yasuo Fukuda, the host of the G8 summit starting Monday.

"I don't have enough experience to give him much advice. It would be arrogant for me," Abe said.

But he added: "If Japan doesn't say what it should, the nation would sink" from the lack of attention.

Abe, an outspoken conservative, took office in 2006 at age 52, making him Japan's youngest premier in modern times.

He quit abruptly in September 2007 after one year in office amid a series of scandals, sliding approval ratings and a crushing election defeat.