The Conservative Party last night strongly criticised Dr Mowlam's statement on the state of the IRA ceasefire.
The party's chairman and former Northern Ireland minister, Mr Michael Ancram, said: "This is an incredible statement that undermines confidence in the peace process."
He said the Northern Secretary's verdict threw into question what it would take for her to conclude that the ceasefire had been broken.
Mr Ancram said: "Dr Mowlam has acknowledged that the IRA has carried out beatings, shootings and murders but illogically states that the ceasefire has not broken down.
"We have seen all take and no give by the paramilitary groups. So far IRA-Sinn Fein have not handed in one ounce of Semtex, while terrorists are being released."
Declaring this position "unacceptable", Mr Ancram continued: "We must ask the question: `What more would it take for the Secretary of State to say the ceasefire has broken down'?"
However, Dr Mowlam won Liberal Democrats backing for "a pragmatic act" designed to maintain the peace process.
The party's Northern Ireland spokesman, Mr Lembit Opik, said: "Mo Mowlam is clearly trying to steer a pragmatic course between declaring the ceasefire over and maintaining the status quo."
He warned terrorists it was "make your mind up time" as it was impossible to claim to support peace while committing acts of violence.