Tehran has told Gulf Arab states it would be "unacceptable" if they allowed use of their airspace or military bases against Iran and warned that any such move would draw a response, a senior Iranian official said.

The official also said any action by Gulf states to balance oil markets should Iranian energy facilities be hit by Israel was not part of the discussions so far, Reuters reported.

The comments come amid growing concern over possible Israeli retaliation for last week's Iranian missile attack, as Iran's Foreign Minister Abbas Araqchi visits Saudi Arabia and other Gulf states including Qatar for talks on Wednesday.

They followed discussions between Iran and Gulf Arab capitals last week on the sidelines of an Asia conference in Qatar, when Gulf states sought to reassure Iran of their neutrality in any conflict between Tehran and Israel.

"Iran made it clear that any action by a Persian Gulf country against Tehran, whether through the use of airspace or military bases, will be regarded by Tehran as an action taken by the entire group, and Tehran will respond accordingly," the senior Iranian official told Reuters.

"The message emphasised the need for regional unity against Israel and the importance of securing stability," he said.

"It also made clear that any assistance to Israel, such as allowing the use of a regional country’s airspace for actions against Iran, is unacceptable."

U.S. President Joe Biden is expected to hold a telephone call on Wednesday with Israeli Prime Minister Benjamin Netanyahu that will include discussion of any plans to strike Iran, according to a person familiar with the matter, read the report.

Washington hopes to weigh in on whether the response is appropriate, a separate person briefed on the discussions said. The White House did not respond to a request for comment.

Biden said last Friday he would think about alternatives to striking Iranian oil fields if he were in Israel's shoes. Last week he also said he would not support Israel striking Iranian nuclear sites.

The Iranian official said Tehran did not discuss the issue of Gulf Arab oil producers raising output if Iranian production were disrupted during any escalation.

U.S. news website Axios, citing Israeli officials, reported last week that Israel could target oil production facilities within Iran as retaliation.

The Organization of Petroleum Exporting Countries, OPEC, which is de-facto led by Saudi Arabia, has enough spare oil capacity to make up any loss of Iranian supply if an Israeli retaliation knocks out some of the country's facilities, Reuters reported.

Much of OPEC's spare capacity is in the Middle East Gulf region. Iran has not threatened to attack Gulf oil facilities but has previously warned that if "Israel supporters" intervene directly their interests in the region would be targeted.

Top oil exporter Saudi Arabia has had a political rapprochement with Tehran in recent years, which has helped ease regional tensions, but relations remain difficult.

Saudi Arabia has been wary of an Iranian strike on its oil facilities since a 2019 attack on its key refinery at Abqaiq briefly shut down more than 5% of global oil supply. Iran denied involvement.

A Western diplomat in the Gulf said that during Thursday's Gulf-Iran meeting in Doha, Iran made clear that Tehran had called for regional unity in the face of an Israeli attack and that it considered neutrality of Gulf states a bare minimum.

The diplomat said Iran had made clear that Tehran would keep a close eye on how each Gulf country responded in the case of an Israeli attack, and also how U.S. bases housed in their countries were used.

Bahrain, Kuwait, Qatar, Saudi Arabia and the United Arab Emirates all host U.S. military facilities or troops.

Two Chinese nationals were killed in an explosion near the international airport of the southern Pakistani city of Karachi on Sunday night, the Chinese embassy in Pakistan said, in what it described as a "terrorist attack", Reuters reported.

In a statement emailed to journalists, separatist militant group Baloch Liberation Army (BLA) claimed the explosion was an attack carried out by them using a vehicle-borne improvised explosive device targeting Chinese nationals, including engineers.

Pakistan broadcaster Geo News reported at least 10 people were injured in the blast in addition to some fatalities. The nature of the blast was not immediately clear, Geo News cited a provincial official as saying.

Karachi police did not immediately respond to request for comment.

The Chinese embassy said a convoy from the Port Qasim Electric Power Company was attacked near the airport, read the report.

"The Chinese Embassy and Consulates General in Pakistan strongly condemn this terrorist attack, express deep condolences to the innocent victims of both countries and sincere sympathies to the injured and (their) families," the statement said, adding the Chinese side has been working with Pakistani authorities in the aftermath.

The BLA seeks independence for the province of Balochistan, located in Pakistan's southwest and bordering on Afghanistan and Iran. In August, it launched coordinated attacks in the province, in which more than 70 people were killed.

BLA specifically targets Chinese interests - in particular the strategic port of Gwadar on the Arabian Sea, accusing Beijing of helping Islamabad exploit the province. It has previously killed Chinese citizens working in the region and attacked Beijing's consulate in Karachi, Reuters reported.

Over 80 police personnel have been injured in clashes with supporters of jailed former Prime Minister Imran Khan taking part in a march near Islamabad, Interior Minister Mohsin Naqvi said on Saturday.

The march, which is being led by the head of the northwestern province of Khyber-Pakhtunkhwa, where Khan's party remains in power, aims to gather in the capital, defying a ban on congregations, to press for Khan's release and agitate against the ruling coalition, Reuters reported.

"The convoy, led by the chief minister, fired on the police and continuously used teargas against law-enforcers," Naqvi told journalists.

He said more than 80 police officers had been treated for injuries since Friday, when clashes broke out just outside the city during an anti-government rally.

Authorities have sealed off Islamabad and blocked cellphone services to prevent the gathering, read the report.

Islamabad is on high alert ahead of a series of top-level diplomatic events scheduled over the next two weeks, including a visit by India's Foreign Minister Subrahmanyam Jaishankar.

Naqvi said while the convoy was heavily armed, the police had been instructed not to carry weapons to prevent the situation from escalating. The government has deployed the army to enhance security in Islamabad.

Khan's Pakistan Tehreek-e-Insaf (PTI) party denies using violence, and says it wants to hold a peaceful gathering.

Naqvi had previously called on the PTI to delay any gathering until after diplomatic engagements in the city, including a Shanghai Cooperation Organisation (SCO) meeting on Oct. 15-16 which will be attended by delegations, including from China, Russia and India.

On Saturday, Naqvi said the authorities had intelligence that the protesters planned to disrupt the SCO conference in a bid to gain attention.

"We can't allow this. I will say to them again, to not cross more red lines - don't make us take extreme steps," Naqvi said.

The PTI, which says the Islamabad protest is just for one day, is also holding a gathering in the eastern city of Lahore on Saturday, where a lockdown of roads is in place, Reuters reported.