Saudi troops clashed with Yemeni Houthi fighters on Tuesday in the heaviest exchange of cross-border fire since the start of a Saudi-led air offensive last week, while Yemen’s foreign minister called for a rapid Arab intervention on the ground.

Saudi Arabia has been leading a coalition of Arab states since last Thursday in an air campaign against the Shi’ite Houthis, who emerged as the most powerful force in the Arabian Peninsula’s poorest country when they seized Yemen’s capital last year.

The Saudis say their aim is to restore President Abd-Rabbu Mansour Hadi, who left the country last week. The Houthis are allied with Saudi Arabia’s regional foe Iran, and backed by army units loyal to longtime ruler Ali Abdullah Saleh, who was pushed out three years ago after “Arab Spring” demonstrations. […]