During his stay in Tehran, the Prime Minister addressed the NAM Summit, where he strongly pitched for coordinated global actions against international terrorism and proliferation of weapons of mass destruction.
He asked the Non-Aligned Movement to take a lead in this and also take a stand based on "universally accepted principles" on Syria.
On Wednesday, Singh met Iranian supreme leader Khamenei and President Mahmoud Ahmadinejad and discussed Tehran's controversial nuclear programme, Afghanistan, tense situation in Syria and other key bilateral issues, including boosting of trade and economic ties.
During his meeting with Zardari yesterday, the Prime Minister pushed Pakistan to act against India-directed terrorism and said that expeditious conclusion of the Mumbai terror attack trial in that country will be a "major" Confidence Building Measure in bilateral relations.
Singh meets Zardari; terror, 26/11 to feature in talks
UNSC past its expiry date, says Khamenei in blistering attack
Iranian nuclear issue, Syrian crisis dominate NAM meet
Singh meets Karzai; hold talks with Syrian PM
PIX: Saif, Grand Marshal at India Day Parade, New York