Northern Ireland's First Minister Peter Robinson has been admitted to hospital after suffering a suspected heart attack.

The 66-year-old DUP leader was rushed to Belfast's Royal Victoria Hospital in an ambulance shortly after 9am today.

A spokesman for the Democratic Unionist Party (DUP) said: "The First Minister felt unwell this morning and has been admitted to the hospital for some further tests."

Senior party sources have confirmed he is being treated for a suspected heart complaint.

A hospital spokeswoman said: "Mr Robinson underwent a procedure this morning and is currently recovering in the Royal Victoria Hospital."

The Robinson family, including disgraced Strangford MLA Iris Robinson, who sparked a scandal in 2010 which led to her husband temporarily standing down, are understood to be at his bedside in the west Belfast hospital.

They have requested privacy at this stage.

Prime Minister David Cameron was among the first politicians to wish Mr Robinson well.

He said on Twitter: "My best wishes to Northern Ireland's First Minister, Peter Robinson, who is in hospital. I hope he has a speedy recovery."

Sinn Fein's Deputy First Minister Martin McGuinness wrote that he was worried.

He said: "Concerned to hear First Minister Peter Robinson has been admitted to hospital. My thoughts & prayers are with him,Iris & family."

DUP deputy leader Nigel Dodds also used Twitter to show his support.

He said: "Best wishes to DUP leader Peter Robinson for a quick and full recovery. All our thoughts are with Peter and family. God bless."

Mike Nesbitt, leader of the Ulster Unionist Party (UUP) has wished the DUP leader a speedy recovery.

He said: "I am sorry to hear that the First Minister has been taken into hospital this morning and I wish Peter a full and speedy recovery.

"Our thoughts are with him and his family."

Pressure has been mounting on Mr Robinson in recent months. His party, which entered into a pact with the UUP, faced one of the toughest elections including the tight battle to regain Belfast East - the seat he lost in 2010 to the cross-community Alliance Party.

Last week, Mr Robinson he announced a reshuffle of his top team at Stormont following the resignation of health minister Jim Wells who caused a furore with comments linking same-sex marriage to child abuse.

Tomorrow, the Northern Ireland Assembly is due to hold a crucial debate on implementation of welfare reform and Mr Robinson has repeatedly warned that the power-sharing institutions are in danger of collapse.