Afghan police opened fire to disperse up to 1,000 protesters in Kabul on Sunday after they burned an effigy of President Barack Obama in protest at American troops allegedly desecrating a copy of the Koran. The protesters blocked roads at Kabul University and outside the national parliament with some shouting: "Death to America Down with Israel" Several students threw stones at riot police, but there were no reports of casualties. Zabiulllah, one of the demonstrators, who were mainly students, said "the people behind this humiliation should be arrested." One banner displayed by the crowd said: "No to democracy. We just want Islam." US forces have denied burning a copy of Islam's holiest book while carrying out a raid last week in Wardak province, south-west of the capital. Captain Elizabeth Mathias, a spokeswoman for the coalition, said an investigation had found the allegation was Taliban propaganda. She said: "We did not burn a Koran ... It is unfortunate that the protesters believe a Taliban rumour." Security remains tense in the capital after President Hamid Karzai agreed to face his rival Abdullah Abdullah in a second round of voting on Nov 7. Both men said yesterday they were determined to press ahead with the election despite hopes in Washington that they might come to an agreement over the make-up of a future government that would dispense with the need for a second vote.