Nearly 20 combatants have been killed in a battle between Afghan troops and Taleban fighters in the southern province of Helmand, officials say.
Some 300 army troops were said to have been involved in fighting
Helmand's deputy governor told the BBC that at one point, he and 100 soldiers were surrounded by 200 Taleban.
He said 16 Taleban and three soldiers had been killed, with 13 more wounded.
The BBC's Paul Wood in Kandahar said it is the most serious fighting between government forces and the Taleban for two years.
Taleban spokesman Qari Mohammad Yousuf denied reports of Taleban deaths, saying only two fighters had been wounded.
The attack comes days after UK Defence Secretary John Reid said 3,300 British troops would be sent to Helmand to help reconstruction efforts there.
The Deputy Governor, Haji Mullah Mir, said that he and the surrounded troops only managed to break through the Taleban after 200 more soldiers arrived to help them.
He said the fighting started after a local police commander travelled to Helmand's Sangeen district in pursuit of Taleban forces from the provincial capital, Lashkar Gah, at about 0700 local time.
A US military spokesman in Kabul said US aircraft, including A-10 attack planes, had also joined in the fighting, the Associated Press (AP) news agency reports.
Mr Mir and his detachment came to the police commander's aid, but found themselves surrounded when the Taleban attacked from four different points.
He said troops retreated because they said civilians could have been killed if the fighting continued.
Earlier this month, an Afghan aid worker was killed in Helmand by suspected Taleban members.