Britain's International Development Secretary Clare Short has condemned the violent battles in Genoa as "unbearable" and called protesters "undemocratic".

But former Labour MP Tony Benn compared the demonstrators at the G8 summit with the Chinese pro-democracy protesters massacred at Tiananmen Square.

They were commenting a day after an Italian protester was shot dead by police. Authorities say the police were acting in self-defence.

Criticising the protesters for being undemocratic, Ms Short said "strong international institutions" were needed to represent the world's governments and to help the struggling countries.

Referring to calls to write off Third World debt, she said: "I think the trouble with the debt campaign is that they're trying to suggest that everything that is wrong for the poor countries can be put right by debt relief. That's not right."

Ms Short told the BBC: "The level of deliberate, really systematic and nasty, nasty, violence is just unbearable. There is a clump of people who set out deliberately to cause real violence. The force they are engaging with is deeply reactionary."

Mr Benn told the BBC: "If this were Tiananmen Square, the Prime Minister and President Bush would be recommending that these guys get the Nobel peace prize.

"When leaders can't meet without mass demonstrations, something is wrong. If they have to meet on a warship, we are back to the medieval castles where the kings met surrounded by the mob.

"I think this might be the beginning of a genuine rethink by decent people. The political class at the moment is absolutely out of touch."

In a statement, the Group of Eight leaders, from the United States, Japan, Germany, France, Britain, Italy, Canada and Russia, expressed "sadness that a human life has been taken", condemned "any form of violence" and urged peaceful demonstrators to set an example for the more militant protesters.