RIYADH, April 12 (Xinhua) -- Saudi air defense forces intercepted on Thursday evening another ballistic missile over border city Jazan fired by the Houthi militia, Al Arabiya local news reported.

On Wednesday, Saudi air defense forces intercepted three ballistic missiles over Saudi Arabia, including one that targeted the capital Riyadh.

The joint forces command of the Saudi-led coalition warned the Iranian-backed Houthi militias of targeting civilian locations or civilians and said that such terrorist acts would be firmly retaliated.

The joint forces command vowed to take all deterrent measures in accordance with international humanitarian law and its customary rules.

The intensity of such attack has increased since the completion of the third year of the coalition's war in Yemen against Houthis in March. The coalition has been accusing Iran of standing behind the militias through weapon supply and other supports.