Shiite mosques in Kuwait City were completely cordoned off, and roads leading to them were closed to traffic, as security men and volunteers stood guard, an AFP reporter said.

A Saudi suicide bomber from the Islamic State of Iraq and Syria (ISIS) group blew himself up in a Shiite mosque last Friday, killing 26 people and wounding 227 others in the worst bombing in Kuwait’s history.

Shiites make up a round a third of the oil-rich Gulf state’s 1.3 million native citizens.

Thousands of Shiite and Sunni worshippers held a rare joint prayer at the Grand Mosque, Kuwait’s largest place of worship for Sunnis.

The emir, Sheikh Sabah al-Ahmad al-Sabah, attended the noon prayers along with the crown prince, parliament speaker and several cabinet ministers and lawmakers.

Armored vehicles, elite forces and policemen stood guard outside the mosque, where the mercury hit 45 degrees Celsius (113 Fahrenheit).

All roads leading to the mosque were off limits to vehicles and worshippers were thoroughly searched before they were allowed inside.

Prayer leader Sheikh Waleed al-Ali, a Sunni, called for national unity and urged Muslims to abandon extremist ideology.

“Extremism has led to this bloodshed,” he said in his sermon.

Both Sunni and Shiite worshippers stood in rows beside each other, each praying according to their tradition.

“Our message today is that Kuwait is united and nothing will ever succeed to divide us,” Abdullah Nuri, a Shiite engineer, told AFP.

“The highly positive reactions by our Sunni brothers after the blast made us very satisfied,” Nuri said.

Shiite cleric Abdullah al-Nejada said: “This is a proof that Sunnis and Shiites are the same and that they (terrorists) will not succeed in dividing this country.”

Kuwait, declaring itself in a state of war against “terrorism,” has placed security forces and the police on high alert.

A large number of suspects have been arrested, and five sent to the public prosecution.

“This is a clear message to terrorists that you will not succeed in your plot. This is the Kuwaiti response to you,” MP Khalil Abul told AFP as he left the mosque.

On Wednesday, parliament approved $400 million (360 million euros) in emergency funding for the interior ministry.

ISIS’ Saudi affiliate, the Najd Province, claimed the bombing and identified the assailant as Abu Suleiman al-Muwahhid.

Kuwaiti authorities have named him as Fahd Suleiman Abdulmohsen al-Qabaa and said he was a Saudi born in 1992.

Gulf interior ministers agreed at the end of a meeting in Kuwait early Friday to boost cooperation to fight terrorism.