World governments Wednesday warned Myanmar’s military rulers they would be held to account for blood spilled in cracking down on mass street protests, with the European Union threatening tougher sanctions.

But there were divisions over the effectiveness of punitive measures with China refusing to put overt pressure on its neighbour and close ally, and even Australia saying it will not order new action.

With witnesses reporting troops firing on protestors and police using tear gas and baton charges, British Prime Minister Gordon Brown called for an urgent UN Security Council meeting and the immediate despatch of a UN envoy to the country still widely known as Burma.

“The whole world is now watching Burma and its illegitimate and repressive regime should know that the whole world is going to hold it to account,” Brown said.

“The age of impunity in neglecting and overriding human rights is over.”

Witnesses in Myanmar’s largest city, Yangon, said at least 17 Buddhist monks had been injured in the violence.

Rights groups called on the UN Security Council to impose its own arms embargo and to stop China and India providing weapons to the junta, while the European Union threatened to “reinforce and strengthen” an existing sanctions regime.

Spain urged “maximum restraint” from Myanmar authorities, with the foreign ministry warning in a statement that any extended crackdown “could have very serious consequences”.

A political solution “can only be found through dialogue and never through the use of force,” the statement said.

France’s President Nicolas Sarkozy was to meet exiled Myanmar activists on Wednesday and Jean-Pierre Jouyet, the junior minister for European affairs, called the military crackdown “unacceptable”.

“I will show France’s support. We do not accept violent repression,” Sarkozy said at the UN General Assembly on Tuesday, where President George W. Bush unveiled new US measures and called for global action to end what he called the junta’s “reign of fear.”

Bush said the US administration would tighten economic sanctions on the junta leaders and their “financial backers”.

The European Union and United States have for years imposed trade and investment sanctions over the junta’s repression of democratic opposition, but the military has shaken off all pressure to change.

Experts said any new sanctions would have to be swiftly followed by vigorous international diplomacy to press the junta to bow to unprecedented public demands for freedom.

Singapore, which chairs the regional ASEAN bloc, said it was “deeply concerned” by the reports of clashes with the protestors and called for “utmost restraint”.

Australia’s Foreign Minister Alexander Downer said his country would not follow the US move in imposing economic sanctions because they “would have absolutely no impact.”

Downer said China was the only country with a hope of convincing Myanmar’s rulers to speed up moves towards political reform.

“I don’t think what Western countries do is likely to lead to sudden changes of direction,” he added.

China and Russia vetoed a UN Security Council resolution in January urging Myanmar’s rulers to free all political detainees.

Amnesty International said the UN Security Council must send a mission to Myanmar to head off violence.

Human Rights Watch called on Myanmar’s allies, including China, Thailand, Russia and India, to urge the regime to address the non-violent protests.

Brad Adams, Asia director at Human Rights Watch, said: “If the military government is going to listen to anyone, it will be countries with which it has close military and economic ties. Now is the time for these countries to show that they care about the health and welfare of the Burmese people.”

Japan, a leading donor to Myanmar, was pressing the junta to “take a calm response” to the protests, Foreign Minister Masahiko Komura said Wednesday, promising only to “carefully monitor developments”.