The United Nations led worldwide condemnation of the bombing of India's embassy in Afghanistan, which left 41 dead in one of the worst attacks in the country since the fall of the Taliban.

The UN Security Council called it a "reprehensible act of terrorism" and expressed concern about the continuing threat posed by the hardline Islamic militant Taliban, who ruled the nation from 1996 to 2001.

UN Secretary General Ban Ki-moon, in Japan for the summit of the Group of Eight wealthy nations, said he condemned the attack "in the strongest terms" and called for those behind it to be brought to justice.

"No political agenda or grievance can justify such reprehensible means," Ban said.

A suicide bomber rammed an explosives-laden car into the Indian embassy in the Afghan capital Kabul on Monday, killing 41 people and wounding nearly 150 others.

The Indian embassy's military attache and a political counsellor were killed along with two Indian guards. The body of one of the diplomats was flung onto the roof of the embassy by the force of the blast and only found hours later.

India is one of Afghanistan's staunchest allies as the war-torn country battles an increasingly bloody Taliban insurgency, and the international community has sent in about 70,000 troops to aid the Afghan government.

The United States, which has the biggest contingent of those troops, called the attack a "needless act of violence" and said it stood with the people of both Afghanistan and India against their "common enemy" of extremism.

"Extremists continue to show their disregard for all human life and their willingness to kill fellow Muslims," US national security spokesman Gordon Johndroe said.

NATO, which altogether leads more than 50,000 troops in the International Security Assistance Force (ISAF) trying to help bolster the government, was also quick to condemn the attack.

"The loss of life and injuries to so many is a tragedy, and a clear attempt to undermine regional relations," NATO Secretary General Jaap de Hoop Scheffer said, calling on all parties to "remain calm in the face of this provocation."

Foreign Minister Frank-Walter Steinmeier of Germany, the third biggest contributor of NATO forces in Afghanistan, said "terrorists" were trying to prevent the establishment of an "orderly and democratic" Afghanistan.

The European Union's External Relations Commissioner Benita Ferrero-Waldner said: "Terrorist attacks will never be a means to achieve anything."

India said those behind the bombing were "no better than the worst criminals" and insisted: "Such acts of terror will not deter us from fulfilling our commitments to the government and people of Afghanistan."

The Afghan government said the attack had been coordinated with and helped by "regional intelligence circles" - an apparent reference to Pakistan.

Kabul has repeatedly accused elements in Pakistan's army and its shadowy intelligence service of giving financial and other support to Taliban and other extremists for strategic interests.

Pakistan itself expressed "profound condolences" over the attack.

"Pakistan condemns terrorism in all its forms and manifestations, as this menace negates the very essence of human values," Foreign Minister Shah Mehmood Qureshi said.