The Irish Republican Army has announced an end to its armed campaign against British rule, and that it will pursue its goals through peaceful means.

The outlawed group said the armed activity ends Thursday. It called on its militants to peacefully work in developing political and democratic programs.

British Prime Minister Tony Blair said the move is a "step of unparalleled magnitude" in the recent history of Northern Ireland. Irish Prime Minister Bertie Ahern and the White House also welcomed the announcement.

Gerry Adams, the leader of the IRA's political wing Sinn Fein, said the move will help revive the peace process.

The IRA said it believes its armed struggle was legitimate - but an alternative exists in ending British rule in Northern Ireland and uniting with Ireland.

The IRA is blamed for the deaths of 1,800 people in its armed campaign, which lasted more than three decades. A cease-fire has been in effect since 1997.

Some information for this report provided by AP and AFP.