Lance Corporal Keys was among the soldiers who died

An investigation is under way into why the Royal Military Police soldiers were gunned down in the southern town of Al Majar al-Kabir on Tuesday.

Reg Keys, whose 20-year-old son Lance Corporal Thomas Richard Keys was among the soldiers killed, said he was concerned the mission appeared to have had little support.

Tributes were paid on Friday to the soldiers at a service at Chichester Cathedral, in West Sussex, near the home of the Royal Military Police training school.

Mr Keys's comments came as a senior British commander vowed the killers would be caught.

Mr Keys, from north Wales, said: "It is not clear at the moment, I must stress that, but it would appear that they sent these six young men into a police station to do a job in a hostile country with hostile elements with very, very little support around them.

"To think that they could get trapped with no immediate support to call upon is of some concern to me."

'Misunderstanding'

Concern has already been raised over British troops patrolling without helmets and flak jackets and maintaining a high profile.

Major General Peter Wall told the BBC investigators were piecing together the events that ended with the six deaths.

"We know that they were in the police station, we know that they were overwhelmed by an aggressive crowd, we know that ultimately, and very sadly, they were all killed".

The patrol had planned to visit several police stations to liaise about policing matters.

But he said: "I can assure you that we will do our utmost to ensure that those responsible are held to account."

RMP TROOPS KILLED IN IRAQ Corporal Simon Miller, 21 Tyne and Wear (pictured) Sergeant Simon Alexander Hamilton-Jewell, 41 from Chessington, Surrey Corporal Russell Aston, 30 Swadlincote, Derbyshire Corporal Paul Graham Long, 24 Colchester Lance-Corporal Benjamin John McGowan Hyde, 23 Northallerton, Yorks Lance-Corporal Thomas Richard Keys, 20 Bala, N Wales The soldiers who died Service to remember the dead

He said there been a "misunderstanding" over weapons searches that could have triggered Tuesday's protests.

Eight members of the 1st Battalion the Parachute Regiment were also wounded that day.

Weapons searches in the town had already been halted due to residents' protests but locals thought troops were about to search their homes.

Soldiers were actually planning to conduct a routine joint patrol with local militia, said General Wall.

Previous searches had caused outrage partly because the Army used sniffer dogs even though the conservative Shia Muslims regard dogs as unclean and because soldiers were accused of disrespect by rifling through women's wardrobes.

The troops were fired on by rocket propelled grenades and a quick reaction force including a helicopter sent to rescue the troops, also came under attack. Some reports said up to four Iraqis were also killed.

At Chichester Cathedral a thanksgiving service had already been arranged for 1130 BST to mark the 200th anniversary of the RMP's Roussillon Barracks in the city.

But an Army spokesman said: "The anniversary will be tinged with sadness following the deaths of six of their colleagues this week in Iraq."

Prayers for the dead soldiers will be led by the Reverend Peter Newman, the Roman Catholic chaplain to the RMP training school at the city barracks.