Five people were killed and 11 others injured on Wednesday in two attacks launched from Yemen on the Saudi border city of Najran, Saudi Press Agency reported.
In one attack, a police jeep was targeted, leaving a security personnel dead and another one injured, spokesperson for local civil defense said.
Shortly, the second attack hit a private car on a road, leaving two civilians who were inside the vehicle, a passer-by and a worker dead.
So far, no one claims responsibility for the attacks.
The two incidents come a day after Yemen's Shiite's Houthi militias attacked homes and a hospital with mortar shells in Najran on Tuesday, leading Saudi authorities to suspend schools and flights to the city until further notice.
Saudi Arabia, along with eight other Arab states, have been bombing the Houthi group and forces loyal to former President Ali Abdullash Saleh since March 26, aiming to restore the rule by the exiled Abd-Rabbu Mansour Hadi.
The coalition forces announced halt of the air raids on April 21, saying they have "eliminated threats of the Shiite group to the regional countries and would turn to focus on political solutions. However, the Saudi-led forces have continued air strikes.