A statement from an emergency meeting of the Organisation of the Islamic Conference (OIC) in Malaysia said the United Nations must act immediately.
"We demand that the UN Security Council fulfil its responsibility for the maintenance of international peace and security without any further delay, by deciding on and enforcing an immediate and comprehensive ceasefire."
The statement said Israel was guilty of "blatant and flagrant violations of human rights" after attacks at Qana and Khiam in southern Lebanon that drew heavy international criticism.
It added, "We strongly condemn the relentless Israeli aggression against Lebanon and the serious violations of the latter's territorial integrity and sovereignty and in this regard charge Israel with full responsibility for the consequences of its aggression."
The meeting also called on the international community to provide support for Lebanon, including through a donors' conferenece to help the nation cope with the "human, social and economic tragedy" it was facing.
Earlier, Ekmeleddin Ihsanoglu, the secretary general of the OIC, had said that the "Islamic Ummah (community) is outraged" over international "double standards" because they do not understand how the human tragedy has been allowed to continue.
"The failure of peace initiatives will endanger not only the peace efforts in the Middle East, but peace and stability in the whole world... another failure in this regard can instigate further violence and terror," he said.
Abdullah Ahmad Badawi, Malaysia's prime minister and chair of the 57-nation body, said that Muslim countries had to commit troops for a proposed UN peacekeeping force in Lebanon.
He said, "We must play a more proactive role in the present conflict. We must show preparedness to contribute forces for peacekeeping operations under the UN banner. Malaysia is ready to do that."
Badawi said the UN had failed to act in Lebanon and that "the Security Council could not even muster the moral courage to condemn Israel for the attack on Qana, or the killing of UN observers at Khiam".
Pakistan echoed Ihsanoglu's comments, warning that continued inaction by the international community over the Middle East conflict would have "incalculable consequences" for regional and world security.
Shaukat Aziz, Pakistan's prime minister, said: "The failure of the international community, especially the UN and the major powers to halt this outrage, is adding to popular anger in the region and around the world.
"This paralysis is dangerous and can have incalculable consequences for long-term peace and security in the sensitive Middle East region and in the world.
"It will also serve a severe blow to the international campaign against terrorism."
About 100 Malaysian Muslim activists demonstrated outside the summit venue as the leaders arrived, chanting anti-Israeli slogans and holding banners that read, "Israelis are real terrorists" and "Don't allow Muslims to be slaughtered".
Lebanon, Egypt, Jordan, Qatar, Saudi Arabia, Syria, Senegal, Indonesia, Iran and Yemen, and the Palestinian Liberation Organization were amongst the countries represented at the meeting.