Washington  - The United States welcomed Iran's decision to attend an international conference on the conflict in Afghanistan scheduled to take place on Tuesday in the Netherlands.

US State Department spokesman Gordon Duguid said, however, there are no plans for US officials to hold "substantive" bilateral meetings with the Iranians on the sidelines of the conference in The Hague.

"A regional conference would be incomplete without Iran," Duguid said. "Iran does share a border with Afghanistan and that border is strategic."

US Secretary of State Hillary Rodham Clinton will lead the US delegation at the gathering, and Richard Holbrooke, the special US envoy for Afghanistan and Pakistan, will also attend. Obama will reveal a revised strategy for Afghanistan on Friday, the White House confirmed.

The United States has strongly backed a conference designed to increase international cooperation in Afghanistan, where the security environment has deteriorated in the last two years as the Taliban steps up its insurgency.

The US military has accused Iran of smuggling weapons into Afghanistan to support the insurgency, and Duguid said the United States will be looking to Iran to begin playing a supportive role.

"What we will do is we will listen to Iran's view of how it can play a positive role and see what they have to offer to the process before we start making any generalizations about where we will go," Duguid said.

Obama has pledged to engage Iran at higher diplomatic levels than in the past. His administration is conducting a review on Iran and has made no announcement in terms of moving forward on that pledge.

Iranian Foreign Ministry spokesman Hassan Ghashghavi said in Tehran Thursday that an Iranian delegation would attend the conference but did not say whether Foreign Minister Manouchehr Mottaki was going.

During a trip to Afghanistan last week, Mottaki denied his country was interfering in Afghanistan.

"Iran has constantly played a positive and constructive role in aiding Afghanistan, and Iran's policy has always been playing a part in reaching solutions for Afghanistan," Mottaki said but refrained to clarify whether he himself would be present in The Hague.

Obama last Friday sent a message to Iran on the occasion of the new Persian year seeking to usher in fresh relations, but has maintained the Islamic state cannot be allowed to acquire nuclear weapons. Iran's Supreme Leader Ayatollah Ali Khamenei responded coolly to Obama's overture, saying a change of US policy in the region would be essential. (dpa)