Iran has accused the United States of double standards over its nuclear deal with India, Iranian media said on Saturday, the day of an informal deadline set by Western officials in a row over Tehran's atomic ambitions.

Syrian President Bashar al-Assad arrived in Tehran, a few weeks after he said he would respond to French President Nicolas Sarkozy's request and use his good ties with Iran to help resolve its nuclear stand-off with Western powers.

He was expected to meet Iranian President Mahmoud Ahmadinejad and other senior officials during a two-day stay. Western powers gave Iran two weeks from July 19 to respond to their offer to hold off from imposing more UN sanctions on the country if it would freeze any expansion of its nuclear work.

That suggested a deadline of Saturday but Iran dismissed the idea of having two weeks to reply. European diplomats in Brussels said they were ready to wait a few more days.

The West accuses Iran of seeking to build nuclear warheads under cover of a civilian power programme. Iran, the world's fourth largest oil producer, denies the charge.

"We have not had any discussion (or) agreement of the so-called timeline of two weeks," Iran's representative to the Vienna-based International Atomic Energy Agency (IAEA), Ali Asghar Soltanieh, told the state Press TV satellite station.

He criticised US policy after governors of the IAEA, the UN nuclear watchdog, on Friday approved an inspections plan for India, an important step towards completing a nuclear trade accord between New Delhi and Washington.

Unlike India, Iran is a signatory to the nuclear Non-Proliferation Treaty (NPT). "Iran expresses its grave concern regarding the double standards used by the United States," Soltanieh was quoted as saying by Iran's ISNA news agency.

He accused the United States of a discriminatory move and of violating the "spirit and letter" of the NPT, while he said Iran faced restrictions and was being "deprived from access to nuclear technology for peaceful purposes," Press TV reported.-Reuters