Iran has notched up several diplomatic coups in the past week despite being cold-shouldered by the West and has shown it has a key role to play in resolving regional issues, experts and envoys said Tuesday.

Topping the harvest of diplomatic successes, they told AFP, are President Mahmoud Ahmadinejad's groundbreaking trip to Lebanon, public acceptance by Washington of Tehran's role in stabilising Afghanistan and the visit to Iran of Iraqi premier Nuri al-Maliki.

Also significant has been the selection of Iran to the influential post of presidency of the Oil Producing and Exporting Countries (OPEC), a first for the Islamic republic since the 1979 revolution.

The OPEC presidency gains significance because key allies of the United States, such as Saudi Arabia, play a decisive role in selecting the candidate to lead what is one of the world's more sensitive bodies.

Far away from its borders, Iran is, additionally, developing ties with emerging powers such as Brazil, which is currently involved with Tehran in a bid to defuse a controversy over Tehran's nuclear programme, and Venezuela, whose firebrand President Hugo Chavez was in Tehran Tuesday on his ninth visit.

These international gains come even as the West increasingly attempts to weaken and isolate Iran, particularly by imposing tough economic sanctions for its refusal to abandon its sensitive uranium enrichment programme.

The diplomatic achievements strengthen Tehran's hand a month before it is due to resume talks with world powers on the nuclear issue, experts say.

The talks have been deadlocked since October 2009 when the last round was held in Geneva.

"The United States cannot restrict Iran's role in the region," said Mohammad Saleh Sedghian, director of the Arab Centre for Iranian Studies in Tehran.

"The policy of economic sanctions may have succeeded to some extent, but it cannot succeed in isolating Iran in the Middle East."

Washington has openly acknowledged Iran's role in the region, especially when it comes to stabilising Afghanistan, while Iraqi Prime Minister Maliki on Monday urged Iran to help rebuild his nation.

"We recognise that Iran... has a role to play in the peaceful settlement of the situation in Afghanistan," said Richard Holbrooke, the US envoy who took part in this week's global conference on Afghanistan held in Rome.

Gholam Reza Ghalandarian, director of the conservative Quds newspaper, told AFP that bagging the OPEC presidency had been a significant boost for Iran.

"Politically, Iran has circumvented the issue of sanctions and isolation," he said, adding that "regional nations and nations outside the region look at Iran as an effective player -- which is why it got the OPEC presidency."

Several Western diplomats too have acknowledged that Iran has scored diplomatically in past days.

"Given the timing, these achievements can be considered as a success for Iran... and nobody disputes Iran's influence in the region," said a Western diplomat on condition of anonymity.

"But the key issue for Tehran is the damage the sanctions are doing to its economy," the diplomat added. "That is what will make its nuclear policy increasingly expensive."

Another Western envoy said that Iran has intensified its diplomatic activity in the Middle East, Asia, Africa and Latin America "to reduce the effects of the punishing sanctions."

"Tehran wants to prove that it is less isolated than the West wants to portray. From this point of view, it may be successful, but outside the region Iran is mostly smoke and noise."

Another Middle Eastern analyst, Amin Kammurieh, said that Ahmadinejad had sought through his controversial visit to Lebanon last week to send a clear message to Washington that Tehran is a key player in the region.

"Iran has become an actor that cannot be ignored because it has some major cards to play in the region," Kammurieh told AFP.

On Tuesday, Iran's envoy to the United Nations, Mohammad Khazai, blatantly touted Iran's "influence" in the region.

"It is necessary for international bodies, especially the UN Security Council, to pay attention to the Islamic Republic of Iran's important and powerful influence in the region and use it to preserve peace and stability in the region and Lebanon," Khazai was quoted as saying by state news agency IRNA.