The deaths came as Operation Panther's Claw was hailed a success
Two UK soldiers have died in separate explosions in southern Afghanistan as an offensive against the Taliban enters its second phase.
Both blasts took place on the morning of 27 July, the Ministry of Defence said. Next of kin have been informed.
The MoD said one of the soldiers died taking part in Operation Panther's Claw - the first death of its second stage.
Earlier, Brig Tim Radford, commander of UK forces in Afghanistan, hailed the operation's first stage as a success.
The latest fatalities take the number of UK service personnel killed in Afghanistan since operations began in 2001 to 191.
Ten UK soldiers died during the first stage of Operation Panther's Claw, an offensive to clear the Taliban from populated areas in north-central Helmand province which has involved 3,000 troops since its launch in June.
According to the MoD, the first of the latest fatalities occurred when a soldier from The Light Dragoons was killed in an explosion whilst on a vehicle patrol as part of the operation in Lashkar Gah district, central Helmand.
It was the first death in Operation Panther's Claw's second stage - which will focus on holding ground won from the Taliban in recent weeks.
In the other incident, a soldier from 5th Regiment Royal Artillery was killed in a blast while on a foot patrol in Sangin district, also in Helmand. This soldier had not been taking part in the operation.
Lt Col Nick Richardson, spokesman for Task Force Helmand, said the MoD was announcing the soldiers' deaths with "deep regret".
He added: "These fine British soldiers paid the ultimate sacrifice and their memory will live with us forever."
The MoD has also named a soldier killed in an explosion during the offensive on Saturday as Bombardier Craig Hopson, 24, from Castleford, west Yorkshire, who was serving with 40th Regiment Royal Artillery.
'Very sad time'
Operation Panther's Claw focused on an area the size of the Isle of Wight, between Helmand's provincial capital, Lashkar Gah, and its economic capital, Gereshk
The first phase of the operation ended as UK Foreign Secretary David Miliband urged Afghanistan's leaders to build a political coalition which included some of the country's more moderate insurgents.
British Prime Minister Gordon Brown said it had been "one of the most difficult summers" since UK forces entered Afghanistan in 2001.
"We have started to break the chain of terror that links Afghanistan to the streets of Britain"
He said the offensive had secured land for around 100,000 people and had started to break the "chain of terror" linking Afghanistan and parts of Pakistan to the UK.
"We mourn their loss and our thoughts and prayers are with their family and friends at this very sad time.
"It's time to commemorate all those soldiers who have given their lives and to thank all our British forces for the determination and professionalism and courage that they've shown," he added.
The Ministry of Defence said the first stage of Panther's Claw was the most heavily-militarised of the offensive.
During the month-long push, troops came across 153 improvised explosive devices, or roadside bombs.
We've had a significant impact on the Taliban in this area - both in terms of their capability and their morale
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