Saudi Arabia said Saturday that the suicide bomber who detonated an explosives-packed vest in a mosque inside a police headquarters, killing 15 people, was one of its own citizens.

Thursday's bombing of a mosque frequented by members of a police special weapons and tactics unit in the southern city of Abha was claimed by the Islamic State group.

Saudi Foreign Minister Adel al-Jubeir will visit Moscow on Tuesday to discuss Syria conflict and the Islamic State group with his Russian counterpart Sergei Lavrov, the Russian foreign ministry said Saturday.

The two ministers last met in Qatar on August 3 when Lavrov, Jubeir and U.S. Secretary of State John Kerry held a three-way meeting, with the situation in Syria topping the agenda.

Pro-government forces in Yemen strengthened by tanks newly supplied by a Saudi-led coalition launched an offensive Saturday to retake the rebel-held capital of Abyan province, military sources said.

A two-pronged drive on the southern province's capital of Zinjibar was launched from the north and south, the sources said.

A Saudi soldier was killed by shelling from across the Yemeni border on Friday, becoming the third death this week, the official SPA news agency reported.

The National Guard serviceman was killed in the Najran region, in the southwest, said the Saudi-led coalition carrying out air strikes against Shiite Huthi rebels in Yemen.

An Islamic State group suicide bomber on Thursday detonated an explosives-packed vest in a mosque inside a Saudi special forces headquarters killing 15 people.

In the latest in a string of IS attacks in the kingdom, the interior ministry said the bomber struck during noon prayers in the city of Abha, in the southern province of Asir near the border with war-strewn Yemen.

Saudi Arabia has sent new military equipment including tanks into Yemen to support loyalists fighting Iran-backed Huthi rebels, tribal and military sources said on Thursday.

"Dozens of tanks, armored vehicles and personnel carriers, as well as hundreds of Yemeni soldiers trained in Saudi Arabia, arrived in Yemen overnight" via the Wadia border post in the north of the country, a Yemeni military source told AFP. 

A Saudi Arabian soldier has been killed in shelling on the border with Yemen, the military said late Wednesday, adding to a rising toll in the kingdom's south over the past week.

"He was hit by a projectile in the sector of Jazan," a Saudi border district, said a statement from the Saudi-led coalition which has been bombing rebels in Yemen for more than four months in support of exiled President Abedrabbo Mansour Hadi.

The United States has delivered more weapons to the Lebanese army as part of the program aimed at assisting the military to confront terrorist organizations, a high-ranking military official said.

The official, who was not identified, said that the delivery of the new batch of heavy weapons is a sign that “Washington has confidence in the capabilities of the military institution and its performance after its success in the battles and the operations it carried out lately.”

Saudi Arabia on Wednesday put to death two Ethiopians, a Pakistani and a Saudi, adding to what a rights group has called a "campaign of death."

The executions -- typically carried out by public beheading -- bring to 114 the number this year, compared with 87 for all of 2014, according to AFP tallies.

Saudi Arabia on Monday beheaded one of its citizens convicted of murder, adding to a sharp increase in executions this year.

Mugrib al-Thanyan was executed in Eastern Province after being found guilty of shooting dead another Saudi after a dispute, the ministry of interior said in a statement.