Saudi Arabia announced on Monday that a strike force had arrived on the border with Yemen.

It happened as Yemen’s Houthi militia and the Saudi-led coalition forces traded heavy artillery and rocket fire in border areas on Monday, residents said, on the eve of a five-day humanitarian truce.

The Houthis said they fired Katyusha rockets and mortars on the Saudi cities of Jazan and Najran on Monday, after the Saudis hit Saada and Hajah provinces with more than 150 rockets.

Saudi planes also struck positions of the Iranian-allied Houthi group in the central city of Taiz and in the oil-producing Marib province east of the capital Sanaa.

A Pakistani expatriate died and four others including a Saudi child were wounded when a mortar launched by the Houthis fell on a school and house in Najran, said a spokesman of the Civil Defense in the region.

In Jazan, a Saudi died and four others including a citizen and three expatriates were wounded when another Houthi mortar fell on a residential area in Harth, said Maj. Yahya Abdullah Al-Qahtani, spokesman of the Civil Defense in Jazan.

The latest fatalities bring to 11 the death toll in Saudi Arabia since the Houthis began firing rockets and mortars over the border last week.

Civil Defense spokesman Ali Al-Shahrani told a local channel that the school and residential area in Najran came under fire at 7 a.m. on Monday.

A group of 17 international aid agencies said on Sunday that five days were not sufficient to provide relief to the country.

Meanwhile, a Moroccan F-16 fighter jet taking part in the anti-Houthi air campaign has gone missing, Morocco’s armed forces said early Monday. The plane had been missing since 6 p.m. the previous day, a statement carried by the state news agency MAP said.

The pilot of a second jet has said he did not see pilot of the missing jet eject. The MAP statement said an investigation was under way into the whereabouts of the missing jet.

On Monday, Houthi militias broadcast a video they said was showing wreckage of the missing jet. Arab News