NEW DELHI - The United States has downplayed the scheduled visit to Iran by Indian Prime Minister Manmohan Singh on August 28, but said Washington hopes the Indian PM will "convey to Tehran the importance of meeting its international obligations", reported Indo-Asian News Service on Wednesday.

"We would hope, as we always do when our partners and allies are involved in any kind of intersection with Iran, that the larger points are made about the importance of Iran coming back into compliance with its international obligations," the US State Department spokesperson Victoria Nuland was quoted as saying on Tuesday.

Tehran could do so "using the opportunity that the P-5+1 (five permanent members of the UN Security Council plus Germany engaged in diplomatic efforts with Iran) has offered for diplomacy to actually make real progress", said the spokeswoman when asked about Singh's trip to Iran to attend the Non-Aligned Movement summit.

The Indian PM's visit to Iran will be the first by an Indian prime minister in over a decade since Atal Bihari Vajpayee's trip in 2001.

The trip is considered significant as it would underline New Delhi's strategic intent to deepen ties with Tehran.

Iran is the second largest oil supplier to India, which does not produce its own crude oil.