His political party says Peter Robinson, the Protestant leader of Northern Ireland's unity government, has been hospitalized after a suspected heart attack.

The 66-year-old leader of the Democratic Unionist Party was admitted Monday to the Ulster Hospital east of Belfast. The Democratic Unionist Party says in a statement he was remaining hospitalized "for some further tests."

The Democratic Unionists, who represent the British territory's Protestant majority, asked media not to contact Robinson's family.

Robinson has been leader of Northern Ireland's five-party government since 2008. A veteran critic of the outlawed Irish Republican Army and its allied Sinn Fein party, Robinson has defied expectations and worked with Irish Catholic colleagues. Among them is former IRA commander Martin McGuinness, who serves as Sinn Fein's top official and effective co-leader of the government.