He said such an attitude did not reflect the aspirations of a government fielding a candidate for the job of secretary-general of the United Nations.

"When the whole world is up in arms about the deaths of four UN observers in Khiyam, Lebanon, how can Thailand, an aspirant for UN leadership, be so conspicuously silent?" said Surin. He was referring to the Israeli Defence Forces' bombing of a UN observation bunker in southern Lebanon that killed four members of a UN Interim Forces in Lebanon (Unifil) unit.

The UN Security Council issued a statement on Thursday expressing "shock and distress" at the severity and the circumstances in which the bombing took place.

Secretary-General Kofi Annan initially described the bombing as "deliberate", an accusation denied by the Israeli government.

Meanwhile, caretaker Deputy Prime Minister Surakiart Sathirathai was at the Asean Ministerial Meeting in Kuala Lumpur, lobbying regional partners, as well as China and the US, for support for his application for the UN's top post.

Surin said: "The entire world is up in arms about the issue, striking at the heart of the UN's peacekeeping role, and we are keeping mum on the case. How could we, in good conscience, claim that we have the interests of the international community at heart?"

He said he could sympathise with caretaker Foreign Minister Kantathi Suphamongkhon being preoccupied at the Asean meeting, "but the rest of the government in Bangkok should have a position - a clear and strong position on this issue of the safety and sanctity of UN personnel".

The situation in the Middle East is threatening world peace, Surin said.

"It has been over two weeks, with over 50 dead and several hundred wounded in Israel, and over 400 killed and 1,300 injured in Lebanon. And there is no end in sight.

"The Thaksin government is still at a loss … not for words, but of a sense of international responsibility.

"It goes to show that we [Thailand] want the world's support for what we consider important to us, but when it comes to [showing] concern for the world, we chose to be silent, stay neutral and keep quiet," he said.