KUALA LUMPUR  - The United States will seek a diplomatic solution with Iran over its controversial nuclear plan, a top US envoy said Friday, as he urged Tehran to play "a responsible role" among Muslim nations. "The United States is committed to securing a diplomatic resolution with Iran on the nuclear issue," Sada Cumber, US special envoy to the 57-member Organisation of the Islamic Conference (OIC), told reporters. "Once that is resolved, there will be enough opportunities with Iran, through the OIC and others, to work on other areas," he added. Cumber described Iran as an important country in the Middle East with considerable influence among Muslims. "We want Iran to play a responsible role in the region and it is an important country," he said. Cumber said the US was committed to ensuring peace in the region and would work with Muslim countries to promote an open society through continuous engagement. "We are looking at only one objective and that is to ensure that there is peace and stability," he said.  "Everywhere America has engaged and has a presence, those societies have opened and they have become more progressive and they are more moderate societies," he said. Cumber, an American-Muslim originally from Pakistan, is visiting Muslim nations within the OIC to bolster ties. After Malaysia, the US envoy will tour Brunei and Indonesia before travelling to Afghanistan. The US suspects Iran's nuclear programme is aimed at developing weapons. But Iran has repeatedly denied the allegations, insisting its programme is aimed solely at providing electricity for a growing population. Along with the threat of new sanctions, Washington has previously warned that the option of military action against Iran remained open if it did not freeze its uranium enrichment programme.