Following the Friday evening prayers angry demonstrators, armed with clubs and knives, gathered in in Martyrs' Square, shouting "no tolerance - execution" and "kill her, kill her by firing squad"

Journalist Andrew Heavens told Sky News: "There were signs that this protest was highly orchestrated. This was not the spontaneous act of a mob."

Gillian Gibbons, 54, was found guilty by a court Thursday for "insulting religion" after she had allowed her primary school pupils to name a teddy bear Mohammed.

She was given a 15-day prison term, of which she will serve the remaining 10 days - after pre-trial detention - in a notorious women's jail in Khartoum.

During the eight-hour trial Thursday, it emerged that Gibbons was arrested after an office assistant at the Christian charity school, Sara Khawad, registered a complaint over the teddy bear to the Ministry of Education.

Her lawyer Kamal al-Gizouli said she had been moved to another prison and that her condition was good. Once Gibbons had served her sentence she would be sent to Britain.

Meanwhile, two Muslim members of the upper house of British parliament planned Saturday to fly to Sudan on a private mission to negotiate the freedom of Gillian Gibbons.

Labour's Lord Ahmed, a Pakistani-born businessman who became Britain's first Muslim peer in 1998, and Baroness Warsi, a lawyer and member of the Conservatives' shadow cabinet, announced the plans for the visit which were welcomed at the Foreign Office.

"Any efforts which complement the efforts which we are making to secure Mrs. (Gillian) Gibbons' release are very welcome," a Foreign Office spokesman said.

The two members of British parliament will held a news conference later Saturday.

Condemnation of the Sudanese decision continued in Britain. In London, Archbishop of Canterbury Rowan Williams told the BBC: "I can't see any justification for this at all. I think this is an absurdly disproportionate response to what is at worst a cultural faux pas."