US Secretary of State John Kerry urged Iran on Thursday to help end wars in Yemen and Syria, where Tehran and its Gulf Arab rivals are backing opposing sides.
On the first visit by a US chief diplomat to Bahrain since 2010, Kerry told authorities in Manama accused of discriminating against the country's Shia majority that respect for human rights was "essential".
Kerry was to meet his Gulf counterparts later Thursday, two weeks before President Barack Obama is scheduled to attend a Gulf Cooperation Council summit in Riyadh when Washington's Middle East policy is likely to come under the microscope.
Kerry called on Iran to "help us end the war in Yemen... help us end the war in Syria, not intensify, and help us to be able to change the dynamics of this region".
He told a news conference in Manama that Tehran should "prove to the world that it wants to be a constructive member of the international community and contribute to peace and stability".
Iran struck last year a landmark deal with world powers on its nuclear ambitions, which has led to the lifting of international sanctions on the Islamic republic.
Bahraini Foreign Minister Sheikh Khalid bin Ahmed Al-Khalifa, whose government accuses Iran of stoking persistent protests among the kingdom's Shias demanding an end to Sunni minority rule, echoed Kerry's call.
"Yes, we do want to see Iran change its foreign policy," he said, speaking alongside Kerry.
All the Gulf Arab states, apart from Oman, are taking part in a Saudi-led coalition that has been battling Iran-backed Shia rebels in Yemen since March last year, in a war which the United Nations says has killed around 6,300 people.
The Arab states of the Gulf have also been staunch backers of Syrian rebel groups fighting to overthrow President Bashar al-Assad's regime since 2011.
Iran, with Russia, has been among the regime's principal supporters in the conflict that has killed more than 270,000 people and pushed nearly five million into exile.
In his meeting with Gulf ministers, Kerry was to discuss "some of the critical regional issues, primarily Yemen, Syria, the situation in Iraq, Lebanon, and elsewhere in the region," a US official said.
The six-nation GCC also includes the Sunni-dominated monarchies of Saudi Arabia, the United Arab Emirates, Qatar, Kuwait and Oman.
Saudi Arabia, Bahrain and the UAE have carried out air strikes against the Islamic State jihadist group in Syria as part of a US-led military coalition.
"We're satisfied, I think, with the overall level of support that we're getting from the Gulf states in the coalition," the US official said.
On Bahrain, Kerry urged authorities to adopt an "inclusive political system".
"Here, as in all nations, we believe that respect for human rights and an inclusive political system are essential," Kerry said.
He said he and Sheikh Khalid "had the chance to discuss the ongoing effort to address and to reduce sectarian divisions here in Bahrain and elsewhere".
"I appreciate the seriousness with which he considers this issue," he said.
"We all welcome steps by sides to create conditions to provide for greater political involvement for the citizens of this great country," he added.
In 2011, the tiny but strategic island state, which is dominated by a ruling family drawn from the Sunni minority, crushed a Shia-led uprising calling for a full constitutional monarchy with an elected prime minister.
Scores of Shias were rounded up and sentenced to lengthy jail terms, including opposition chiefs.
Amnesty International urged Bahraini authorities earlier this month to "immediately and unconditionally" release jailed opposition figures.
"The alarming erosion of human rights in Bahrain in recent years means that anyone who dares to criticise the authorities or call for reform risks severe punishment," said Amnesty's regional deputy director James Lynch.