Jeddah, Saudi Arabia - he secretary general of the Organisation of the Islamic Conference (OIC) expressed his condolences for the bombings in London that killed at least 50 people and injured hundreds.
Ekmeleddin Ihsanoglu sent a message to Prime Minister Tony Blair expressing his "utmost indignation and outrage" and condemning, "in the strongest terms, these horrendous acts," an OIC statement said.
He expressed his solidarity with Blair and the British people "in their resolve to fight terrorism and uttered his confidence that the solidarity of the civilized world will overcome the scourge of terrorism."
The Muslim World League, based in the holy city of Mecca, also denounced Thursday's "criminal and ugly act which aimed at killing innocent civilians."
Islam "categorically and unequivocally prohibits" such crimes, said secretary general Abdullah al-Turki in a statement carried by the official Saudi Press Agency.
He called on the United Nations to "undertake a collective and coordinated action to combat terrorism ... which has no country or nationality and is not affiliated to any religion."