RIYADH, Saudi Arabia — Four gunmen attacked a Saudi security patrol near the Iraqi border early Monday, killing three soldiers and wounding at least three more, the kingdom's Interior Ministry said.
A Saudi security official told The Associated Press the gunmen had come from inside Iraq. He spoke anonymously because he was not authorized to release the information.
It was the first deadly attack along Saudi Arabia's 745-mile (1,200-kilometer) border with Iraq since the kingdom joined the U.S.-led coalition conducting airstrikes against Islamic State militants in Syria. The IS group controls about a third of both Syria and Iraq.
No group immediately claimed responsibility for Monday's attack.
Interior Ministry spokesman Mansour al-Turki said four "terrorists" had fired on the patrol at around 4:30 a.m. (1:30 a.m. GMT) in the Northern Borders Province. Saudi government websites said the commander of the border guard in the area, Brig. Gen. Oud Awad al-Balawi, was among those killed.
The Interior Ministry said the guards returned fire, killing two attackers. The other two tried to flee and hide, the ministry said. When security forces approached them, one of the attackers detonated his explosives belt and blew himself up. The fourth was shot dead by security forces.
The government-linked Sabq news website reported that the gunmen were armed with hand grenades, pistols and explosive belts.
Residents in the area told the AP that Saudi military aircraft could be seen overhead throughout the day.
In November, the kingdom ordered residents living near the Iraqi border to relocate for at least a year in order to widen the buffer zone to 12 miles (20 kilometers). The order also included widening buffer zones in the Eastern Province border city of Hafr al-Batin, near Kuwait and Iraq, and Tabuk Province, near Jordan.
The decision was announced around the same time that IS leader Abu Bakr al-Baghdadi called on supporters to launch attacks inside Saudi Arabia in retaliation for the airstrikes.
Saudi Arabia has spent billions of dollars reinforcing security and building a heavily fortified fence along the border following the U.S.-led war in Iraq and its violent aftermath.