SANAA, Yemen (AP) — Yemeni military officials close to the country's Shiite Houthi rebels said Thursday that the rebels are trading fire with warships from the Saudi-led military coalition near the Bab al-Mandab straight, the strategic southern entrance to the Red Sea and the gateway to the Suez Canal.

The development comes amid land clashes Thursday near the straight between units loyal to President Abed Rabbo Mansour Hadi and rebel forces.

The pro-Hadi units were backed by air support from the Saudi-led coalition that has been bombing Houthi positions and has sent reinforcements from the nearby southern port city of Aden, according to security and military officials, who have remained neutral in the conflict that has splintered the country.

The Houthis have been in control of the strategic area for several months and still control the vast majority of the area near Bab al-Mandab, according to the officials.

The U.N. says at least 2,355 civilians have been killed in fighting in Yemen since March, when a Saudi-led coalition began launching airstrikes against Houthis and allied army units. The Houthis have been in control of the capital Sanaa since last September and are at war with the internationally recognized government as well as southern separatists, local militias and Sunni extremists.

Saudi and Egyptian warships have been deployed off the coast of Yemen to secure the strategically vital Bab el-Mandab. The straight is one of the world's busiest shipping lanes, a major route for oil from the Gulf and cargo between Europe and Asia.

All officials spoke on condition of anonymity because they were not authorized to speak to reporters.

Separately, a Saudi security officer was killed Thursday in heavy cross-border fire with attackers in Yemen, Interior Ministry spokesman Maj. Gen. Mansour al-Turki said in statement.

A number of Saudi soldiers have been killed in cross-border fire and shelling with Houthi fighters in the past few months since a Saudi-led coalition began a campaign of airstrikes against the rebels.

A soldier from the United Arab Emirates died from injuries sustained in September in Marib province, a major battleground east of Sanaa, the UAE's state-run Emirates News Agency said Thursday.