NEW DELHI: A big Iranian trade mission will arrive in India on Sunday to explore commercial opportunities on the same day as US Secretary of State Hillary Clinton starts her official visit, officials said.

The six-day Iranian trip comes as Washington has been pressuring India to reduce its oil purchases from Iran in a bid to coax the Islamic republic to abandon its disputed nuclear programme.

“The timing of the visit with Mrs Clinton's arrival is a coincidence,”Anand Seth, a spokesman for the Federation of Indian Export Organisations (FIEO), a quasi-government body under the Indian trade ministry, said Saturday.

“They’re returning our visit. We invited them when we were there (in Iran),” he told AFP. An 80-member Indian trade mission spent five days in Iran in March.

The 56-member Iranian delegation is set to arrive in India on the same day Clinton lands to spend two days in the energy-hungry South Asian nation, which hopes to win a waiver from tough US sanctions on Iran.

India and China, whose growing economies depend heavily on fuel imports, have publicly opposed US sanctions but at the same time have quietly been diversifying oil sources as a June deadline looms for a US decision on sanctions on importers of the Islamic republic's oil.

India has pushed state-run refiners to diversify their imports from Iran to win a waiver from sanctions and is aiming to cut shipments from the Persian Gulf nation by 15 to 20 per cent.

“India has cut back on its oil imports from Iran, it has not been insensitive to American concerns (about Iran),” TP Sreenivasan, ex-Indian ambassador to the UN, told AFP.

The United States say Iran's nuclear drive is aimed at making an atomic bomb but Iran says it is for civilian energy.

The Iranian delegation will also travel to financial hub Mumbai and meet with local trade bodies.

India has been walking a diplomatic tightrope as it seeks to drum up more exports from Iran while managing its growing relations with the United States.

India has been buying around $11 billion worth of oil from Iran a year -- its second largest supplier after Saudi Arabia -- but sells Tehran just $2.7 billion in goods.

India needs to increase its exports to Iran as the intensifying Western sanctions campaign against Iran dries up dollar and euro payment routes that New Delhi was using to pay for Iranian oil imports.

India and Iran have worked out a deal under which New Delhi will seek to pay for close to half of its Iranian oil imports in rupees. The rupee payments will be used by Iran to purchase Indian goods.

India, which has strong historical ties with Tehran, views Iran as an important counterweight to arch-rival Pakistan in the troubled region.

India, which has one of the world's largest Muslim populations, is also uneasy about joining a US-led drive against the Islamic republic that could have domestic political repercussions, analysts say.