Omar, believed to be sheltered by fiercely conservative tribesman on the Afghan-Pakistan border, said the increase in troops meant battles would ''flare up'' everywhere.

In a statement posted on the internet on Sunday, Omar said, ''The current armed clashes, which now number into tens, will spiral up to hundred of armed clashes. Your current casualties of hundreds will jack up to thousand casualties of dead and injured.''

Violence in Afghanistan has spiked in the past two years, and 2008 has been the deadliest year for US troops since the 2001 invasion to oust the Taliban for playing host to al-Qaeda chief Osama bin Laden.

More than 60,000 foreign troops, including 32,000 Americans, are stationed in Afghanistan. Although US troop levels are already at their highest level since 2001, US commanders have requested 20,000 more troops to stem the increase in violence which has engulfed parts of the country.

The rising violence in Afghanistan appears to be coordinated closely with the spike in militant attacks in neighbouring Pakistan, and officials increasingly view both countries as part of the same battlefront.

Militants in Pakistan's north-western city of Peshawar attacked a truck terminal yesterday, torching more than 100 military vehicles loaded with supplies for American and coalition forces in Afghanistan.

The attack was the second in two days on the supply line, and showed its vulnerability to militants who control large swaths of Pakistan's lawless regions close to Afghanistan.

Omar's message, released at the start of the Muslim holiday of Eid al-Adha, or the Feast of the Sacrifice, also rejected any talks with the Government of Afghan President Hamid Karzai while foreign troops remain in the country.

Mr Karzai, during an Eid address yesterday, again asked armed militants to lay down their weapons.

Mr Karzai offered protection last month for Omar wanted by the US and blacklisted by the UN if he accepted Afghanistan's constitution and joined peace talks.

Omar dismissed that call. ''Do not ever presume that in the presence of the occupation forces the followers of the path of Islamic resistance will ever abandon their legitimate struggle merely on your empty and farcical pledges, material privileges and personal immunity.'' AP