At least 100 people have been killed or wounded in an explosion targeting Shiite Muslims at a mosque in northern Afghanistan, according to a Taliban police official.

Dost Mohammad Obaida said the “majority of them have been killed”.

The blast occurred during the Friday prayer service at the Gozar-e-Sayed Abad Mosque in Kunduz province, when members of the Shiite minority typically go in large numbers for worship.

If confirmed, the death toll would be the highest in an attack by militants since US and Nato troops left Afghanistan at the end of August and the Taliban took control.

Witness Ali Reza said he was praying at the time of the explosion and reported seeing many casualties.

Taliban chief spokesman Zabihullah Mujahid said Taliban special forces had arrived at the scene and were investigating the incident.

The cause of the blast was not immediately clear. No group has claimed responsibility.

The Taliban leadership has been grappling with a growing threat from the local affiliate of the so-called Islamic State group, known as the Islamic State in Khorasan.

IS militants have ramped up attacks to target their rivals, including two deadly bombings in Kabul.

IS has also targeted Afghanistan’s religious minorities in attacks.

Religious authorities in a Malaysian state denounced Shi’ite Islam on Friday and asked mosques to call in sermons on their congregations to be vigilant over the spread of the “deviant teachings” of the Shi’ite sect.

The minority Shi’ite community in Sunni Muslim-majority Malaysia has been subject to discrimination and persecution by authorities, human rights groups have said.

State religious departments have raided the community’s places of worship and made arrests.

The Selangor Islamic Religious Department, or JAIS as it is known by its Malay-language acronym, said in a weekly sermon that Muslims should not be influenced by practices of the Shi’ite sect.

Sermons in Malaysia are standardised, and Islamic leaders typically deliver their Friday sermon in mosques based on the weekly sermon issued by the state religious department.

“I implore upon the Muslim ummah (community) to always remain vigilant upon the spread of Shee’ah deviant teachings in this nation,” the department said, according to a copy of the sermon posted on its website.

JAIS is the Islamic religious authority in Selangor, Malaysia’s richest state. It is funded by the state government.

The Shi’ite ideology “ensnares its victims” through educational institutions, children’s books, novels, comics, among others, the department said in the sermon said.

“The Muslim ummah must become the eyes and the ears for the religious authorities when stumbling upon activities that are suspicious, disguising under the pretext of Islam,” it said.

The department described Shi’ite practices as “extremist” and “nauseating”.

Reuters could not establish if the sermon criticising Shi’ites was delivered at all mosques in the state. But religious experts said mosques typically follow the sermon issued by the state religious authority.

Isham Pawan Ahmad, an associate professor at the International Islamic University near Kuala Lumpur, said the sermon delivered at a mosque he went to in Selangor on Friday was similar to the one issued by JAIS.

“This is the most vehement comment on Shi’ites in Malaysia. It makes them a target,” Isham said.

Shi’ites are a minority is Malaysia, with some estimating their numbers in only the tens of thousands.

Shi’ite community leaders were not immediately available for comment.

In 1996, a Malaysian Islamic body issued a fatwa, an Islamic ruling, recognising Sunni Islam as the faith of Malaysian Muslims.

Malaysian Shi’ite Muslims have complained about their inability to worship freely, and that they may face obstacles in carrying out rituals which are both cultural and religious, the U.N. special rapporteur in the field of cultural rights said in a preliminary report in 2017.

Saudi Arabia has agreed to admit an Iranian diplomat to head an office representing Iranian interests in the kingdom, the official Iranian news agency IRNA reported on Sunday, in a rare move after the rivals broke off relations in 2016.

“An informed diplomatic source said Sunday that Saudi Arabia had agreed to grant a visa to the head … of Iran’s interests section,” IRNA reported. “Observers saw this … as a positive diplomatic step in Tehran-Riyadh relations.”

The office is expected to be set up within the Swiss diplomatic mission in Saudi Arabia, based on an agreement signed in 2017.

There was no immediate official Saudi reaction to the Iranian report.

The kingdom, the regional rival of mostly Shi’ite Iran, presents itself as the guardian of Islamic orthodoxy and custodian of its holiest places in Mecca and Medina.

Riyadh severed diplomatic relations after Iranian protesters stormed the Saudi Embassy in Tehran following the execution of a Shi’ite cleric in Saudi Arabia in January 2016.

Both countries agreed to Switzerland’s offer of its traditional policy of good offices and to act as a diplomatic channel between the two countries.

Saudi Arabia welcomed President Donald Trump’s decision in May to withdraw the United States from an international nuclear agreement with Iran and to reimpose economic sanctions on Tehran.

In an interview published on the Iranian Foreign Ministry’s website, the ministry spokesman said there had been a “breakthrough” in relations between the two regional rivals.

“Up until two weeks ago, no visa had been issued for the names that we had submitted a long time ago,” spokesman Bahram Qasemi said.

“But within the last week or two, there has been a breakthrough and I think there are indications that the office for the protection of interests will be opened,” he added.

Tension between the two countries have surged in recent years, with Saudi Arabia and Iran supporting opposite sides in wars in Syria and Yemen and rival political parties in Iraq and Lebanon.

The world’s largest cemetery, in Iraq’s Shi’ite holy city of Najaf, is expanding at double its usual rate as the nation’s death rate increased with the war on Islamic State.

The Wadi al-Salam cemetery, Arabic for “Peace Valley,” has a special place in the hearts of Shi’ite Muslims as it surrounds  the Mausoleum of their first imam, Ali Bin Abi Talib, a cousin and son-in-law of Prophet Mohammad.

The pace of daily burials rose to 150-200 after Islamic State, the ultra-hardline Sunni group overran a third of the country in 2014,  said Jihad Abu Saybi, a historian of the cemetery. The rate was 80-120 a day previously, he said.

Shi’ite paramilitary often visit Ali’s golden-domed shrine before heading to the frontlines to battle Islamic State, and request to be laid to rest in Wadi al-Salam should they be killed, as a reward for their sacrifice.

As land becomes scarce, the cost of a standard 25 square metre family burial lot has risen to about 5 million Iraqi dinars ($4100) almost double the amount paid for the same lots before violence escalated as IS exerted control over large swathes of north and western Iraq in 2014.

Millions of graves of different shapes lie in the roughly 10 square km (4 square miles) cemetery that attracts burials from Shiites all over the world. By nationality, Iraq’s Iranian neighbours are thought to come second in number people interred near Ali’s golden-domed shrine.

Often built with baked bricks and plaster, decorated with Koranic calligraphy, some graves are above ground tombs, reflecting the wealth of those within.