A Saudi soldier has been killed and another injured in a shooting attack on their patrol vehicle in the kingdom's eastern province of Qatif.

Saudi Arabia's official news agency on Friday quoted the Saudi interior ministry as saying that the attack took place late on Thursday. It gave no further details, but said that authorities were investigating.

In recent months, Qatif, a Shia-majority province, has seen a series of attacks targeting security forces.

Last week, two security personnel were injured when a roadside bomb hit their car in Qatif.

Thursday's attack came days after Saudi Arabia executed four Shias convicted on "terrorism" charges for attacks on the police and their role in violent protests.

The interior ministry said the four were executed for incidents that took place in Qatif.