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Iran's foreign minister, visiting Beirut on Tuesday, blasted the U.N. Security Council for failing to stop the Israel-Hezbollah conflict and called the U.S. and Israel "partners in these brutal crimes" against Lebanese civilians.

His words echoed Iranian President Mahmoud Ahmadinejad, who said Tuesday that the U.S. and Britain were accomplices in the Israeli attacks against civilian targets in Lebanon.

"It has become clear that they (the U.S. and Britain) are not competent to sit on the U.N. Security Council and enjoy veto rights. They are culprits, criminals themselves. They must stand trial," he said in a speech to supporters in the city of Bojnoord, in northeastern Iran, broadcast live on state-run Iranian television.

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"The U.S. and Britain are accomplices in all crimes committed by the occupying Zionist regime and have to answer to these crimes," he said, drawing shouts of "Death to America!" from the crowd.

Ahmadinejad called for an immediate stop to the fighting.

The Iranian foreign minister, Manouchehr Mottaki, told reporters in Beirut that "the U.N. Security Council has proven its uselessness and ineffectiveness during this (Israeli) aggression."

Speaking to reporters after a meeting with Lebanese President Emile Lahoud, a strong Hezbollah ally, he also accused the United States, without naming it, of complicity in bringing about the death and destruction caused by Israel's 20-day-old offensive in Lebanon.

"We think that the protectors of the Zionist entity and those who support it are partners in these brutal crimes being committed against the innocent women and children" of Lebanon, Mottaki said.

At a news conference before leaving the Lebanese capital, Mottaki insisted there be an immediate cease-fire, opening the way for negotiations.

When asked about the international and Israeli demand for the disarmament of Hezbollah, the top Iranian diplomat ducked the question.

"We will support anything that all the sides in Lebanon can unanimously agree on," he said.

He said he had not met Hebollah leader Sheik Hassan Nasrallah, as he traditionally has done on past visits to Lebanon.

"The aim of my visit was to declare our support for the Lebanese government, people and resistance in the face of Israeli aggression," he said.

Nasrallah has gone underground since the Hezbollah-Israeli fighting broke out three weeks ago. Israeli warplanes have destroyed his residence and office in south Beirut, but he has since given televised speeches.

Mottaki arrived in Lebanon on Monday, in the first visit by an Iranian official to war-torn Lebanon since fighting broke out between Israel and Hezbollah guerrillas three weeks ago. He traveled over land from neighboring Syria, since the country's only international airport was bombed in the first days of the war.

On Monday night, Mottaki met with Lebanese Foreign Minister Fawzi Salloukh and with French Foreign Minister Philippe Douste-Blazy, who was in Beirut for the third time since Hezbollah captured two Israeli soldiers on July 12 — triggering the Israeli offensive that has killed hundreds of people, mostly civilians.

Both meetings took place at the Iranian Embassy late Monday, but participants made no comments to the press.

Mottaki's visit coincided with a call on Muslim states by a top Iranian hard-line cleric, Ayatollah Ahmad Jannati, to provide weapons to Hezbollah to use in its fight against Israel, according to the semi-official Iranian Students News Agency.

"Now, it is expected that Muslim states not spare any assistance to Hezbollah and the Lebanese people, especially providing weapons, medicine and food," Jannati told ISNA.

It was not immediately clear if Jannati's comments represented the Iranian government. Jannati is the head of the powerful Guardian Council, a constitutional watchdog arbitrating between the parliament and the Iranian government.

Mottaki's visit comes a day after Israeli warplanes bombed a house in the southern Lebanese town of Qana, killing at least 56 civilians and provoking worldwide condemnation.

"Iran stresses the need for an immediate halt to the aggression launched by the Zionist entity on Lebanon," Mottaki said during a news conference Monday.

Mottaki also criticized the U.N. Security Council's inability to stop the conflict.

"The public opinion in the Islamic world and the international community are daily and frankly condemning the Israeli attacks on Lebanon, while we see international organizations are keeping silent," he said.

Iran and Syria are the principal sponsors of Hezbollah, and the two countries have applauded Hezbollah's capture of two Israeli soldiers, which triggered the Israeli offensive in Lebanon that has killed hundreds of Lebanese, most civilians.

Complete coverage of the Mideast conflict available in FOXNews.com's Mideast Center.