Gordon Brown: 'This is the frontline against the Taleban'
The number of British troops in Afghanistan will increase by 300, Prime Minister Gordon Brown has told MPs.
Total deployment will rise to 8,300 from March until August next year, with the extra soldiers carrying out "security" operations.
In his statement, Mr Brown called on some of Britain's allies to contribute more "fairly" to military efforts.
The Conservatives said ministers had to be more "realistic" about the aims of the mission to Afghanistan mission.
The Ministry of Defence said a small reserve battalion would be going to Afghanistan, but would not say from which regiment.
Mr Brown's statement to the Commons came after he visited Afghanistan over the weekend, holding talks with president Hamid Karzai and meeting British troops.
He said: "It's been a hard year for our soldiers but it's been a much harder year for our enemies, who found they cannot defeat us."
Mr Brown said Afghan national income had risen by 70% and that refugees were coming back to the country.
But he called for "proper burden-sharing" among the 41 coalition countries in Afghanistan.
He added that the "burden is not always shared equally. It's vital that all members of the coalition contribute fairly".
A Nato meeting next April would discuss the issue, he added.
Conservative leader David Cameron said the UK and its allies had to avoid setting "unrealistic" expectations for the Afghanistan mission.
Liberal Democrat leader Nick Clegg said any efforts to establish peace would need a "regional agreement", with Nato countries talking to China, Russia and Iran.