Afghanistan braces for Qur'an protests
Kabul - Afghan authorities braced for a fourth day of violent protests over the burning of copies of the Qur'an by the US military.
This came despite calls for calm from the president and an apology from US President Barack Obama.
"We are extra vigilant," interior ministry spokesperson Sediq Sediqqi said.
"We've had two reports of demonstrations, small demonstrations. But it's OK now. Nothing to worry about," Sediqqi said. "The police are on alert, of course."
Riot-control police had been deployed in Kabul, officials said.
Many Afghan and foreign nationals have expressed fear of revenge after the weekly Friday prayers, especially if some radical clerics incite more violence.
The Taliban on Thursday called on Muslim Afghans to "beat and kill" foreigners to avenge the incineration of copies of the Qur'an by US troops on Monday.
Call for restraint
Riots broke out across the country after the incident and at least 17 people have been killed, including two US soldiers who were shot by a man wearing the Afghan National Police uniform.
An investigation delegation set up by Afghan President Hamid Karzai called the burning an "insulting and shameful act".
The delegation also asked "all our Muslim citizens of Afghanistan to exercise self-restraint and extra vigilance in dealing with the issue".
"Nato officials promised to meet the Afghan nation's demand of bringing to justice, through an open trial, those responsible for the incident," a statement by the presidential palace said late on Thursday.
The Nato-led International Security Assistance Force (ISAF) said on Friday a joint investigation with Afghan authorities was looking into the "events surrounding the mishandling of religious materials".
"I call on everyone throughout the country - ISAF members and Afghans -to exercise patience and restraint as we continue to gather the facts," said John Allen, the commander of the Nato-led forces, in the statement.