UPDATE 1-One British soldier killed in Afghanistan

LONDON, July 5 (Reuters) - A British soldier has been killed in an explosion in southern Afghanistan on Sunday, the Defence Ministry said, the fifth to die in five days as UK forces take part in a major U.S.-led offensive against Taliban strongholds.

The Ministry of Defence (MoD) said the soldier from the 1st Battalion Welsh Guards was killed by a blast in an operation near Gereshk in central Helmand Province. Next of kin have been informed.

The MoD said the death raises the number of British troops to have died to 174 since Britain joined the United States and other countries in invading Afghanistan in 2001.

Lieutenant Colonel Nick Richardson, spokesman for the British military's Task Force Helmand in Afghanistan, said: "It is with extreme sadness that I must report the death of a brave soldier.

"He laid down his life for his country and for the good people of Afghanistan. We grieve for his loss and join with his family and friends to mourn his passing. He will always be remembered."

The death comes after two British soldiers were killed in separate incidents near Gereshk during the same operation on Saturday evening.

One soldier was killed by a rocket propelled grenade attack and the other by a contact explosion, the MoD said.

Two other British troops were killed in the area on Wednesday. One of them, Lieutenant Colonel Rupert Thorneloe, was the highest ranking British soldier to be killed in the conflict in Afghanistan.

Thousands of U.S. and British forces launched a large-scale operation in southern Afghanistan this week to try to drive the Taliban back and retake territory in the biggest offensive since U.S. President Barack Obama assumed office in January. (Reporting by Christina Fincher and Stefano Ambrogi; Editing by Jon Hemming)