TEHRAN — The 120-nation Nonaligned Movement handed its host Iran a diplomatic victory on Friday, unanimously decreeing support for the disputed Iranian nuclear energy program and criticizing the American-led attempt to isolate and punish Iran with unilateral economic sanctions.

But the group’s communiqué, issued by Iranian state news media at the end of its annual meeting, omitted any mention of support for Syria, Iran’s vital Middle East ally, which appeared to reflect a view among many members that the Syrian government’s attempt to crush the uprising there was indefensible.

The conspicuous omission of Syria from the document, called the Tehran Declaration, followed a dramatic day of maneuvering by Iran’s delegation to secure some kind of support for Syria’s government, diplomats said, as the supreme leader, Ayatollah Ali Khamenei, and his aides were criticizing foreign backing of the Syrian insurgency.

Nonetheless for Iran, the final result of the Nonaligned Movement’s meeting, the biggest international gathering in Iran since the 1979 Islamic Revolution, amounted to the strongest expression of support for Iran’s nuclear energy rights in its showdown with the West. The unanimous backing of the final document undercut the American argument that Iran was an isolated outlier nation.