Taliban fighters mounted a coordinated assault on the northern city of Kunduz overnight, attacking from four directions and entering urban areas and threatening a repeat of the operation in which they seized the city exactly a year ago.
Sheer Ali Kamawal, commander of the 808 Tandar police zone in Kunduz, said the attack began at around midnight (1930 GMT Sunday) and fighting was still going on in and around the city. Some Taliban fighters had entrenched themselves in residents' houses.
Military helicopters flew overhead and gunfire could be heard in Kunduz, where Afghan troops backed by American air strikes and special forces were fighting a year ago to the day to drive out insurgents who had raised the Taliban flag in the city centre.
Police spokesman Mahfozullah Akbari said security forces were preparing an operation to drive out the fighters, who had set up in the Khak Kani area in the south-west of the city.
"The Taliban are inside some civilian houses and we have to carry out operations very carefully," he said.
A statement from the interior ministry said reinforcements were being sent to the city.
Monday's attack, a day before the start of a major donor conference in Brussels, underlines the precarious security situation in Afghanistan, where government forces are estimated to have control over no more than two-thirds of the country.
"A massive operation started on Kunduz capital from four directions early this morning," Taliban spokesman Zabihullah Mujahid said in his official Twitter account.
He said the Nawabad area with four checkpoints had been captured and a number of soldiers had been killed. It was not immediately possible to verify the claim, Reuters reported.