Dissident republicans have said they killed the three men

Thousands of people have attended a series of rallies across NI to show their anger at the murders of two soldiers and a policeman.

Silent protests took place in Belfast, Lisburn, Newry, Downpatrick and Londonderry.

A peace vigil is also to be held in Craigavon, County Armagh, near the site where Constable Stephen Paul Carroll was shot dead on Monday.

Two people are still being questioned over the murder of the 48-year-old.

Prime Minister Gordon Brown has sent words of support to MPs who held a vigil outside Westminster in support of the peace rallies held in Northern Ireland.

Mr Brown's official spokesman said the prime minister was "very supportive of anything that signified unity".

Rallies

Speaking in Belfast, Eugene McGlone of the Unite union, which helped organise the rallies, described the turnout as "very heartening".

"There was probably in excess of 10,000 people," he said.

"There were I suppose some apprehensions on the part of some of our people as to whether or not we would get a crowd out at such short notice."

In Londonderry, Inspector John Burrows said everyone in the police service appreciated the public's support.

"We are massively grateful for the people of Derry who've turned out to support the police," he said.

"They have come to show solidarity, I believe, with the police and to send a very clear message out to the people who killed Constable Stephen Carroll and the two soldiers that they do not represent them."

On Wednesday, during prime minister's questions, Gordon Brown spoke of the "courage and dedication" of the security forces.

They have come to show solidarity, I believe, with the police and to send a very clear message out to the people who killed Constable Stephen Carroll and the two soldiers that they do not represent them  Inspector John Burrows Standing in silence for peace In pictures: NI peace rallies

He said they showed the "defiance and determination" of people to "stand up to the evil of criminal violence".

Conservative leader David Cameron, returning to work after the death of his son Ivan, condemned the "callous killers".

He said the most important thing was that everyone worked with the police to ensure the killers could be found and convicted.

'Abominable acts'

In Dublin, Taoiseach Brian Cowen said those who carried out the attacks were a "tiny and unrepresentative group of evil people who have no mandate and no support for their actions".

Pope Benedict XVI has added his voice to the condemnation, calling the murders "abominable acts of terrorism".

A reward of £100,000 for information leading to the arrest and conviction of the killers of Constable Carroll and two soldiers has been offered by the Sun newspaper in conjunction with the Crimestoppers charity.

Dissident republican group, the Continuity IRA, said it shot Constable Carroll at Lismore Manor, in Craigavon, on Monday.

On Saturday, sappers Mark Quinsey, 23, from Birmingham, and Patrick Azimkar, 21, from London, were shot at Massereene Army base, Antrim.

The Real IRA said they killed the soldiers, who died in a hail of bullets as they accepted a pizza delivery at about 2120 GMT.

Four men were also injured in the attack. One of them is in a critical condition and another is seriously ill.

A youth aged 17 and a 37-year-old man remain in police custody for questioning in connection with the murder of Constable Carroll.

'Increased threat'

There were minor disturbances in Craigavon on Tuesday night, where wheeled bins were set on fire after the police raids.

Meanwhile, serving and former police officers due to give evidence to the Robert Hamill inquiry have been granted temporary anonymity.

The ruling was made following Constable Carroll's murder and what the inquiry chairman said was the "increased security threat" to police officers in Northern Ireland.

Police chiefs from Northern Ireland and the Irish Republic are to meet on Thursday to assess the security threat posed by dissident republicans.

Chief Constable Sir Hugh Orde and Garda Siochána Commissoner Fachtna Murphy will meet in Belfast.

British and Irish ministers met for a security summit at Hillsborough Castle in County Down on Tuesday, where they pledged the attacks would not be allowed to derail the peace process.