Condemning the bombing, the United States said it has offered assistance to probe the attack to find out those responsible behind it.

"We condemn these attacks. And in the incident in Kabul, we have offered assistance, not only to Afghan but also to Indian authorities, in terms of follow-up, determining who's responsible for these attacks," State Department spokesman Sean McCormack said.

US National Security spokesman Gordon Johndroe had earlier condemned the deadly attack yesterday in which at least 41 people, including four Indians, were killed.

In Brussels, NATO Secretary General Jaap de Hoop Scheffer said the attack was a clear attempt to undermine regional relations.

"I call on all parties to remain calm in the face of this provocation. The alliance remains determined to continue its mission to help bring security and stability to Afghanistan, including against the scourge of terrorism," Scheffer said.

The British Foreign Secretary David Miliband said the attack was designed to undermine the efforts of democratic governments and the international community to bring peace and stability to the region.

"The perpetrators of such atrocities will not succeed," Miliband said.

The UN Security Council condemned the attack and called for international efforts to bring the perpetrators, organisers, financiers and sponsors of this ‘reprehensible act’ to justice.

In a consensus presidential statement, the 15-member Council also urged all governments to ‘cooperate actively’ with the Afghan authorities to probe the attack.

It reaffirmed the need to combat by all means threats to international peace and security caused by terrorist acts.

UN Secretary-General Ban Ki-moon and General Assembly President Srgjan Kerim have also called for vigorous steps to bring the perpetrators to justice.

In separate statements, Ban asserted that no political agenda or grievance can justify such ‘reprehensive means’ and Kerim said such terrorist acts are ‘unacceptable in all their forms and manifestations committed by whosoever, wherever and for whatever purposes’.

In Sapporo in Japan, Chinese President Hu Jintao denounced the attack.

"We strongly denounce the terrorist attack on the Indian Embassy. I sincerely express my heartfelt condolences to the families of those killed in the bombing in Afghanistan," Hu told Prime Minister Manmohan Singh when they met on the sidelines of the G-8 summit.