Irans Ambassador to the United Nations Human Rights Council (UNHRC) Mohsen Naziri Asl has warned military action in Syria will spark a deeper crisis and stir a regional war.
"Military action risks igniting a regional war," the Iranian ambassador told the Geneva-based council on Monday.
"The only way out of this situation is the immediate negotiation end the conflict," he added.
The Iranian envoy made the comments after UN High Commissioner for Human Rights Navi Pillay on Monday warned against the ramifications of a military action in Syria.
"This appalling situation cries out for international action, yet a military response or the continued supply of arms risk igniting a regional conflagration, possibly resulting in many more deaths and even more widespread misery," she said.
The United States has been seeking to win international support for waging a war against Syria after foreign-backed opposition forces accused the government of President Bashar al-Assad of launching a chemical attack on militant strongholds in the suburbs of Damascus on August 21.
Damascus has denied the accusation, saying the attack was carried out by militants themselves as a false-flag operation.
Obama has said that Washington must take military action against the Syrian government, which would mean a unilateral military strike without a UN mandate.
Speaking to CBS Television on Monday, President Assad warned of massive retaliation if the United States launches a military strike against Syria, saying Washington should "expect everything" if US forces attack his country.
The US Senate will vote on authorizing military intervention in Syria later this week.
The White House has admitted it has no "irrefutable" evidence of Syrian government's use of chemical weapons, but said a "strong common-sense test irrespective of the intelligence" suggested the Syrian army was responsible for the August poison gas attack.