Afghanistan's Taliban insurgents said on Monday they were drawing up a response to an offer from President Hamid Karzai of safe passage for insurgent leaders who wanted to talk peace. Karzai, back from a trip to Britain and the United States, said on Sunday he would guarantee the safety of Taliban leader Mullah Mohammad Omar if he was prepared to negotiate. With the Taliban insurgency intensifying seven years after the hardline Islamists were forced from power, the possibility of talks with more moderate Taliban leaders is increasingly being considered, both in Afghanistan and among its allies. The Taliban have ruled out any talks in the past as long as foreign troops remain in Afghanistan, but Karzai said on Sunday that condition was unacceptable. A Taliban spokesman, Zabihullah Mujahid, declined to comment on Karzai's comments but said a Taliban reaction would be issued. "We are preparing a reaction and will put it in a statement later today," Mujahid said by telephone from an undisclosed location. Violence in Afghanistan has surged over the past two years, raising doubts about prospects for the country and its Western-backed government.