Russia and China are urging the UN atomic agency to soften or even not issue an eagerly awaited report detailing Iran's suspected efforts to develop nuclear weapons, diplomats told AFP on Tuesday.

"It does seem like the Russians and Chinese are pressuring the IAEA (International Atomic Energy Agency) to refrain from reporting on the possible military dimensions of Iran's nuclear programme," one Western diplomat said.

Another Western envoy to the agency said however that they expected the IAEA head, Yukiya Amano, to resist such pressure and publish the report the week before a November 17-18 meeting of the 35-member IAEA board, as planned.

What Amano says in the report "is not going to be a reflection on who has bent his ear in one direction or the other," the Vienna-based diplomat told AFP on condition of anonymity.

Russia, which helped Iran build its only functioning nuclear power plant at Bushehr, and China, have traditionally taken a softer stance on Iran than fellow veto-holding UN Security Council powers the United States, Britain and France.

Previous IAEA reports have concentrated on Iran's efforts to enrich uranium, which would give it the fissile material needed to produce electricity or medical isotopes, or, if purified further, nuclear weapons.

Amano said in a September report he was "increasingly concerned" about such activities, calling the IAEA's information "extensive and comprehensive and ... acquired both from many (IAEA) member states and through its own efforts."

In another report in May, Amano had listed seven areas of concern including testing high explosives, studies of detonators and design work on arming missiles with a nuclear payload.

But the new one is expected to address what the IAEA calls the "possible military dimension," meaning Iran's alleged research into putting the fissile material in a warhead and the development of ballistic missiles.

Iran, which has been hit by four rounds of UN Security Council resolutions, says its nuclear activities are peaceful and in the past has dismissed such allegations as fabricated.

On the same day as the reports of pressure from Beijing and Moscow, Russia announced it has sent mobile radar jammers to Iran and is negotiating future deliveries that it believes do not contravene UN sanctions against the regime.

"This is a defensive system," the military and technical cooperation agency's deputy director Konstantin Biryulin was quoted as saying by the state RIA Novosti news agency.

"We are in constant talks with Iran over that country's purchases of military technology that does not fall under UN sanctions," he added.

Meanwhile, diplomats said it is too early to say what the IAEA board will do if and when it receives the report on Iran in its regular meeting next month. One possibility might be another referral to the Security Council.

US-Iranian relations are already fraught, hot on the heels of US accusations -- rejected by Iran -- that Tehran was behind an alleged plot for a Mexican drug cartel to kill the Saudi ambassador to Washington.

Analysts are divided over how far Iran is from having the bomb, but most agree it is making progress on all areas that would allow it to do so, despite sanctions, the Stuxnet computer virus and the assassination of scientists.

Tehran last year began enriching uranium to 20 percent, taking it a substantial step closer to being able to enrich to a weapons-ready purity of 90 percent, and has begun fitting out a hard-to-bomb mountain bunker at Fordo.

Experts say it will be hard for the IAEA to find a "smoking gun" in Iran proving conclusively that the Islamic republic is developing nuclear weapons, and that this has been ordered from the top of the regime.

"The Iranians have been masters in compartmentalising their nuclear programme," Mark Hibbs from the Carnegie Endowment for International Peace think-tank said earlier this month.

"Some scientists who have been doing research that looks like it may be related to nuclear weapons development aren't even aware that they are part of the nuclear programme."