WASHINGTON (AFP) - Exiled former Iranian lawmakers on Thursday proposed a compromise to avert conflict over Teheran's nuclear program, calling for an end to sensitive uranium enrichment and an easing of United States-led sanctions.

In a letter sent to US President Barack Obama, Iran's supreme leader Ayatollah Ali Khameini and the European Union, the seven ex-MPs said that a solution to the crisis was possible if all sides sought a "win-win" outcome.

The former lawmakers, who support greater freedoms inside Iran, proposed that the clerical regime halt enrichment of uranium of fissile purities of 20 perc ent, a level that could be used for a nuclear bomb if further enriched.

Iran would put its 20 per cent stockpile under monitoring of the UN International Atomic Energy Agency, which would carry out inspections of the nuclear programme.

Iran would enjoy the right to enrichment at lower levels as well as guarantees of sufficient fuel to research reactors for peaceful use.

In turn, the US and five other nations negotiating with Iran - Britain, China, France, Germany and Russia - would lay out a clear timetable to ease sanctions that the lawmakers said have caused pain in the country.

Fatemeh Haghighatjoo, a former reformist member of the Iranian parliament who lives in Boston, said that the sweeping Western sanctions helped bring Teheran to talks but doubted they would change the regime's behavior further.

"We know how these sanctions actually hurt. Even people can't get enough medicine," she said at the Woodrow Wilson Centre for International Scholars.

"Anti-West sentiment will be increased if sanctions keep continuing and we will gradually lose this social capital" of the population's positive feelings toward the West, she said.

Ali Akbar Mousavi, another former reformist lawmaker who lives in the US, said Khamenei "needs at least a small victory," such as official Western recognition of the right to enrichment at purely civilian levels.

"He wants to say to competitors... 'Look, I won and you lost,'" Mr Mousavi said.

The US has voiced disappointment over Iran's response to international talks and has steadily ramped up sanctions, including trying to ban all exports of oil, its key source of foreign exchange.

US-ally Israel has refused to rule out a military strike, and American officials have repeatedly said they will do whatever it takes to stop Iran getting a nuclear weapon.

Iran says that its programme is for peaceful purposes. US intelligence has not concluded that the regime has taken the decision to build a nuclear bomb.