Afghan President Hamid Karzai, centre, surrounded by bodyguards, takes a rare walk through Kandahar City on Monday. (Allauddin Khan/Associated Press)

Afghan President Hamid Karzai twice threatened to quit politics and join the Taliban if the West continued to pressure him to enact reforms, legislators said Monday.

Karzai issued the threat during a private meeting with Afghan lawmakers on the weekend. People at the meeting said they thought Karzai's comments were aimed at hardline members of parliament.

The comment is the latest in a string of outbursts that have drawn criticism from foreign backers. Last week, Karzai accused the UN and the international community of carrying out a "vast fraud" as part of a plot to deny him re-election.

White House spokesperson Robert Gibbs called the latest Karzai remarks troubling.

"On behalf of the American people, we're frustrated with the remarks," he told reporters on Monday.

The comments came to light as Karzai paid a visit to the Kandahar City area south of Kabul. It was his first visit to the volatile south in almost 15 months.

Karzai criticized for violence

The Afghan president toured one community where dozens of residents died in an explosion several weeks ago. Local residents said they lived in constant fear and sharply criticized him for not doing enough to stop the violence.

Later, community leaders told Karzai they were worried about NATO's planned spring offensive, when troops are expected to launch the largest operation in the eight-year-old war against the Taliban.

But Karzai told the local leaders there wouldn't be an offensive.

"Our partners are here to help, but we run this country as Afghans," Karzai said.

A U.S. general who was with Karzai at the meeting remained silent.

NATO forces are under intense pressure to minimize civilian casualties, because the deaths of innocents undermine Karzai's precarious hold on power and boost support for the insurgency.

On Monday, NATO confirmed that international soldiers were responsible for the deaths of five civilians in February, including three women.

NATO also announced Monday that its soldiers killed 10 militants in an early morning raid on a compound near the Pakistani border. No civilians were harmed, the military organization said.

With files from The Associated Press and Laurie Graham