Fugitive Taleban leader Mullah Mohammad Omar has vowed stepped up violence against U.S.-led forces in Afghanistan. Coalition forces say they are prepared.

The rarely photographed Mullah Mohammed Omar is reportedly seen in this undated photo

The latest threat came Thursday, apparently from former Taleban leader Mullah Omar. In a statement given to news agencies, Omar claimed that hundreds of young Afghans were signing up to become suicide bombers.

The statement says that a new wave of violence would be unleashed at the beginning of summer, and would be directed at U.S.-led forces providing security in Afghanistan's fledgling democracy.

U.S. commanders say there is usually a spike in militant attacks during the warmer weather, as snow melts and mountain passes reopen.

Coalition spokesman Colonel James Yonts says counter-insurgency operations will continue as planned.

"We expect these attacks, but we will not be deterred," he said. "We will stand strong, and we are committed in Afghanistan, with the Afghan government and the Afghan people."

The Afghan government is also downplaying the significance of the Taleban threat.

"The fact is that, at the end of each season, they say the same thing, that they increase their attacks on Afghan security forces," said Interior Ministry spokesman, Yousuf Stanizai.

The Taleban insurgency has taken more than 1,500 lives in the past year. That is the highest death toll since coalition forces ousted the hard-line Islamic Taleban regime in 2001 for harboring al-Qaida terrorist leader Osama bin Laden.

Suicide bombings have intensified, with at least 12 this year alone.

The Interior Ministry's Yousuf Stanizai says this tactic is a sign of weakness, and that Taleban militants no longer have the stomach for a head-on fight.

"As I say before, they don't have the power to fight the international coalition, or Afghan security forces," he said.

NATO security forces are being reinforced and expanded throughout the volatile southern provinces where Taleban insurgents are most active.

Some 18,000 U.S. troops are also leading independent missions specifically targeting al-Qaida and Taleban militants.