Iran's foreign minister called on Sunday for a united front among all Middle Eastern nations to fight militancy, in his first regional trip after reaching a nuclear deal with world powers that raised concerns among Iran's Gulf Arab neighbours.

"Any threat to one country is a threat to all... No country can solve regional problems without the help of others," Mohammad Javad Zarif said at a news conference hosted by the Iranian embassy in Kuwait.

Zarif earlier met Emir Sheikh Sabah al-Ahmed al-Sabah and his Kuwaiti counterpart, Sheikh Sabah al-Khaled al-Sabah, who was not present at the press conference.

Zarif began the one-day, three-country tour by visiting Kuwait. He was due to go on to Qatar and then Iraq.

Most Gulf Arab states are worried that Iran's July 14 accord will hasten detente between Tehran and Washington, emboldening Tehran to increase backing for Middle Eastern allies at odds with Gulf Arab countries.

"Iran stands behind the people in the region to fight against the threat of extremism, terrorism and sectarianism... Our message to the regional countries is that we should fight together against this shared challange," Zarif added.

Most Sunni Muslim-ruled Gulf Arab states have long accused Tehran of interference in Arab affairs, alleging financial or armed support for political movements in countries including Bahrain, Yemen and Lebanon.

Shi'ite power Iran denies interference but says the nuclear deal will not change its policies in the region.

"OPPRESSED NATIONS"

Ahead of his Gulf visit, Zarif said in a statement posted on his ministry's website late on Friday that Tehran would continue supporting its allies in Syria and Iraq to fight against militant group Islamic State.

Echoing that message in a speech earlier on Sunday, Iranian President Hassan Rouhani said on a visit to Iran's Kurdistan Province: "The Iranian nation supports all oppressed nations."

"If it wasn't for Iran, Erbil and Baghdad would have also fallen to the terrorists (of Islamic State) ... Just as we defended Dahuk, Erbil and Sulaymaniyah (in Iraqi Kurdistan), if any country in the whole region is a victim of aggression, the Iranian nation will defend the oppressed," Rouhani added.

Bahrain said on Saturday it had foiled an arms smuggling plot by two Bahrainis with ties to Iran and announced the recall of the Gulf island kingdom's ambassador to Tehran for consultations after what it said were repeated hostile Iranian statements.

Commenting on the allegation, Iranian deputy foreign minister Hassan Ghashghavi noted Bahrain's government disagreed with Iran's "support of oppressed people in their country".

"However we will continue doing so and we insist that the oppressed people of Bahrain need attention," he said. - Reuters