Taliban leader says his followers will keep fighting if US-Afghan security deal is signed

The leader of the Afghan Taliban says his group will keep fighting if Kabul signs a key security deal with the United States.

The secretive Mullah Mohammad Omar also urged followers to step up their militant campaign against the Afghan government and NATO forces.

He also called on Afghans to boycott next year's presidential and provincial elections.

Monday's message from the Taliban leader came in an email distributed to media on the eve of the Muslim Eid al-Adha holiday.

Violence across Afghanistan has spiked as insurgents try to retake territory ahead of full NATO pullout at the end of 2014.

President Hamid Karzai and U.S. Secretary of State John Kerry reached a preliminary agreement on the U.S.-Afghan deal on Saturday but key issues, such as immunity for American troops, remain.