In attack that shocks quiet Oman, gunmen kill 6 and wound dozens more at a Shiite mosque

DUBAI, United Arab Emirates — Several gunmen burst into a Shiite mosque in the Gulf Arab state of Oman and opened fire, killing six people and wounding nearly 30 more, authorities said Tuesday, stunning the peaceful sultanate and making it the country's deadliest such attack in recent memory.

The Islamic State extremist group, through an affiliated news agency, claimed responsibility for the attack in the capital, Muscat, without providing evidence. It marked the first time that the Sunni Muslim extremist group has asserted responsibility for an attack in Oman.

That the Islamic State, which considers Shiites to be heretics, targeted Shiite worshippers on the eve of their holy day is nothing new — the group in January claimed responsibility for an attack in Shiite-majority Iran that killed 84 people.

Most shocking, analysts say, is that the attack happened in Oman, a quiet country on the southeastern edge of the Arabian peninsula with well-trained security forces, a policy of non-intervention and a majority population of Ibadi Muslims, a more liberal offshoot of Islam predating the Sunni-Shiite split.

''It illustrates that ISIS thinks outside of the box and tries to do things that most people think wouldn't be possible, taking advantage of small failures within security architectures of different countries,'' said Aaron Y. Zelin, a senior fellow at the Washington Institute for Near East Policy.

There is no known branch of the Islamic State in Oman, a country that tends to stay out of the sectarian disputes roiling the wider region. But Islamic extremists, including branches of the Islamic State and al-Qaida, have a foothold in neighboring war-torn Yemen.

The Royal Oman Police said the shooting killed five worshippers in the mosque in Muscat's Wadi Kabir neighborhood and one police officer. Omani authorities did not specify the number of gunmen or provide their nationalities but said security forces had killed three attackers.

Pakistan identified four of the dead as its citizens. Nearly 2 million migrants, many from Pakistan and elsewhere in South Asia, help power Oman's economy by filling low-skilled jobs in construction and other fields.

Analysts described the rare shooting as the latest example that the Islamic State, after losing its territory in Iraq and Syria some five years ago, is seeking to strike farther afield.

''It's part of their reorganization from being a group with most of its actions in Iraq and Syria to using their resources in a global network," Zelin said, citing the deadly attack in March on a Moscow concert hall and other bombings claimed by the group's regional affiliate, Islamic State Khorasan, across Afghanistan and Pakistan. ''It makes them more resilient in some ways."

The U.S. Embassy in Muscat issued a security alert, warning citizens to ''stay vigilant.''

Like other sheikhdoms in the Persian Gulf, Oman retains tight controls on traditional media. Its state news agencies on Tuesday praised authorities' success in containing the chaos but offered scant information about the state of investigations or the attack itself.

Statements of condolence and outrage came from around the region, where Oman plays a sensitive role.

The sultanate maintains friendly relations both with Saudi Arabia, the heartland of traditionalist Sunni Islam, and its regional rival, the Shiite power Iran. The Iranian Foreign Ministry said it stood ''in solidarity with Oman against such attempts to sow discord.''