Syria's top diplomat told the world's nations Saturday that his country's belief in military victory is greater now because the army "is making great strides in its war against terrorism" with support from Russia, Iran and Lebanon's Hezbollah fighters.

Foreign Minister Walid al-Moallem said Syria is more determined than ever to eliminate "terrorism" from the country. The Syrian government refers to all those fighting to overthrow President Bashar Assad as "terrorists," including Western-backed opposition groups.

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Al-Moallem accused the "moderate armed opposition" of committing crimes and massacres against Syrians "that are no less barbaric" than those of the Islamic State extremist group and al-Qaida. The Syrian government in turn has been accused by the U.S. and other Western nations of the indiscriminate killing of civilians, dropping bombs filled with chlorine gas as a chemical weapon, and torturing and killing opponents.

The Syrian official addressed the UN General Assembly's annual ministerial meeting after frantic but unsuccessful efforts by the U.S. and Russian foreign ministers to revive a cease-fire that came into effect on Sept. 12 but collapsed after a week following attacks by both sides. The truce was aimed at enabling the delivery of desperately needed humanitarian aid and paving the way for a resumption of talks between the government and opposition.

Open gallery view Syria's Foreign Minister Walid al-Moallem addresses the 71st session of the United Nations General Assembly at U.N. headquarters, Saturday, Sept. 24, 2016. Credit: AP / Jason DeCrow

Syria was stepping up its military campaign even as talks were taking place between U.S. Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov on the sidelines of the UN meeting on reviving the cease-fire.

As of Saturday, rebel-held parts of the city of Aleppo had come under a blistering wave of airstrikes that residents said was without precedent in the 5 1/2-year conflict which has killed over 300,000 people and driven half the country's population from their homes. The airstrikes killed dozens, toppled buildings and sent wounded people flooding into poorly equipped clinics.

Aid was never delivered to Aleppo, and on Saturday government forces captured an area on the edge of the city, tightening their siege around the rebel-held east.

Global reaction was swift and condemned the new Syrian offensive in harsh terms.

UN Secretary-General Ban Ki-moon "is appalled by the chilling military escalation" in Aleppo and underlines that the use of indiscriminate weapons including incendiary devices and bunker buster bombs in densely populated areas "may amount to war crimes," his spokesman said, adding that Ban considers this "a dark day for the global commitment to protect civilians."

U.S. Secretary of State John Kerry, called the bombing of Aleppo "beyond the pale," accusing the Syrian government of "laying siege in medieval terms to an entire community." Speaking at Tufts University in Boston, he demanded that Russia help bring peace to Syria instead of "an unacceptable precedent ... for the entire world."

Al-Moallem said the Syrian government remains committed to political negotiations in Geneva under UN auspices but he stressed that any solution must follow two parallel tracks: intensified counter-terrorism efforts and an intra-Syrian dialogue that allows Syrians to determine their future "without foreign interference."

He said a political solution should begin "by establishing a government of national unity comprising representatives from the government and the opposition, in all its factions, and tasked with creating a constitution drafting committee."

Once a new constitution is approved by Syrians through a referendum, he said, parliamentary elections should follow leading to formation of a new government.

That proposal is contrary to the roadmap for a Syrian political transition adopted by key nations in Geneva in June 2012 including the five permanent UN Security Council members — the U.S., Russia, China, Britain and France — that has been the basis of subsequent Geneva talks.

It starts with the establishment of a transitional governing body, vested with full executive powers, and ends with elections, and requires Assad to relinquish power at some unspecified point.

Al-Moallem made no mention of Assad stepping down as president and envisioned a military victory — something Russia, the U.S. and the UN say is impossible.

"Our belief in victory is even greater now that the Syrian Arab Army is making great strides in its war against terrorism, with the support of the true friends of the Syrian people, notably the Russian Federation, Iran and the Lebanese national resistance," al-Moallem said. He was referring to Lebanon's Shiite Hezbollah militia.

Syria's uprising began in March 2011 with mostly peaceful protests against the Assad family's four-decade rule, but escalated into a civil war following a brutal government crackdown and the rise of an armed insurgency.

Al-Moallem accused Qatar and Saudi Arabia of spreading "terrorism" in Syria by sending in "mercenaries equipped with the most sophisticated weapons." He also accused Turkey of opening its border "to let in tens of thousands of terrorists from all over the world," and providing them with military and logistical support.

The Syrian minister reiterated the government's condemnation "in the strongest possible terms" of a U.S. attack on a Syrian army site near Deir El-Zour airport on Sept. 17, which he said allowed Islamic State fighters to gain control of the site.

"The Syrian government holds the United States fully responsible for this aggression, because facts show that it was an intentional attack, and not an error, even if the United States claims otherwise," he said.

Al-Moallem also accused Turkey of "flagrant aggression" for entering Syrian territory "under the pretext of countering terrorism" and said this "must be stopped immediately.