The future of Iraq depends on a battle between good and evil, the prime minister has said.

Tony Blair was speaking in Downing Street following talks with Jordan's King Abdullah.

His comments came after a series of explosions in Karbala and Baghdad resulted in over 140 deaths.

Over 400 people were injured by what appeared to be a coordinated series of attacks on Iraqi Shias as they celebrated the climax of a holy ritual.

Blair said the worshippers had been exercising their new religious freedoms and had been killed in a "cruel and evil way".

Those behind the attacks were trying to set the different religious communities against each other, the prime minister warned.

He said the "vast majority" of Iraqis wanted a free, stable, prosperous and democratic nation.

"The fact that this happens... is an indication of how stark is the difference now between the Iraqis themselves, those from other countries such as Britain and America who are trying to help them rebuild their country...and that small but I'm afraid highly active group of terrorists who are prepared to bomb and kill and main innocent people in order to wreck the progress that is being made," he said.

"If there is any clearer struggle between good and evil, it is between those on the one hand who want to build Iraq as a decent country - in which people from whatever religious quarter can live together in freedom and in peace on the one hand - and on the other those who would destroy that and replace that by religious hatred."

Liberal Democrat foreign affairs spokesman Sir Menzies Campbell also condemned the attacks.

"These incidents, with such terrible loss of life, simply underscore the enormous security problems attached to the political and economic reconstruction of Iraq," he said.

"No-one disputes the principle that Iraq should be handed back to the Iraqi people as soon as possible.

"But it is clear from today that no matter the constitutional position a formidable British and American security contribution is going to be essential for a considerable time to come if stability is to be achieved."