Iran's top leader Ayatollah Ali Khamenei urged visiting Iraqi Prime Minister Adel Abdul Mahdi on Saturday to ensure US troops leave "as soon as possible", Iranian state media reported.
"You must make sure that the Americans withdraw their troops from Iraq as soon as possible because expelling them has become difficult whenever they have had a long military presence in a country," Ayatollah Khamenei was quoted as saying.
Mr Abdul Mahdi arrived in Tehran on Saturday morning, leading a senior delegation, for the two-day state visit.
He was pictured sitting in a room alongside the Iranian supreme leader, the country’s highest religious figure, and Hassan Rouhani, the country’s moderate president.
Details of the Iraqi premier’s schedule for the rest of the trip remain unannounced.
Before meeting Ayatollah Khamenei, he held a joint press conference with Mr Rouhani, in which the Iranian leader pledged that the country wanted to end the three-year war in Yemen, despite international criticism that it is prolonging the conflict.
"The war in Yemen should finish soon and the solution to the Yemeni crisis should be a political one," he said.
Tehran supports the Houthi rebels in Yemen who are fighting against a Saudi-led coalition supporting the Yemeni government.
He also called for Iran and Iraq to expand their gas and electricity dealings and boost bilateral trade to $20 billion, state TV reported, despite difficulties caused by US sanctions against Tehran.
"The plans to export electricity and gas and hopefully oil continue and we are ready to expand these contacts not only for the two countries but also for other countries in the region," Mr Rouhani said
In March, the United States granted Iraq a 90-day waiver exempting it from sanctions to buy energy from Iran, the latest extension allowing Baghdad to keep purchasing electricity from its neighbour.
Iran and Iraq fought a devastating 1980-88 war but the 2003 US-led invasion of Iraq that ousted Saddam Hussein prompted a long Sunni extremist insurgency during which Iran’s regional sway rose at the expense of the United States.