Iran considers Syrian President Bashar al-Assad its closest regional ally and has not accepted US intelligence that the regime killed some 1,400 people in a chemical weapons attack last month.
"My government strongly condemns the use of chemical weapons in Syria," Rouhani told a New York think tank forum, without assigning blame.
Also Read
"This is an issue of concern not only to us but also to many other countries, which requires cooperation and joint efforts aimed at finding a durable, inter-Syrian political solution."
Iran, led by a Shiite theocracy, opposed the 1996-2001 rule in Afghanistan of the Taliban, who welcomed Al-Qaeda militants and enforced an austere brand of Sunni Islam.
The secular-minded Assad belongs to the heterodox Alawite community and is battling rebels who include Sunni hardliners.
In an earlier false start of better ties, Iran and the United States briefly cooperated in 2001 when a US-led campaign ousted the Taliban.
Rouhani welcomed a US-Russian agreement for Assad to give up chemical weapons, which halted a push for a military strike on Syria by US President Barack Obama.
"We are pleased that diplomacy... And sober judgment prevailed over saber-rattling," Rouhani said.
Iran itself was a victim of chemical weapons used by Iraq, a history acknowledged by Obama in his address to the United Nations earlier this week.
Western powers largely supported Iraqi president Saddam Hussein in his 1980-88 war against Iran.
Rouhani, elected in June on a platform of moderation, is on a visit to the United Nations aimed largely at easing tensions with Western powers over Iran's contested nuclear program.
US Secretary of State John Kerry held a brief but historic meeting yesterday with Iranian Foreign Minister Mohammad Javad Zarif, who said that he agreed with major powers to seek a deal within a year to resolve concerns over Tehran's nuclear program.
But despite the upbeat tone, the United States was cool to letting Iran participate in a peace conference in Geneva on ending Syria's civil war, the next step after a UN Security Council resolution enforcing the US-Russian chemical weapons agreement.
A senior US official, speaking on condition of anonymity, said that Iran first had to commit to the declaration of the first Geneva conference last year that called for a political transition in which Assad would leave.
"Anyone who wants to participate has to, at the very least, sign up to the Geneva communique and Iran has not explicitly done so," the official said.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
)