Israel has stepped up the readiness of its naval forces amid growing concern over advances by Yemen’s Houthi group near the strategic Bab el-Mandeb Strait, the Israeli newspaper Yedioth Ahronoth reported Sunday.

The daily said Israel’s security establishment is closely monitoring developments after the Houthis expanded their presence along Yemen’s Red Sea coast and strengthened their position around the key waterway.

Israeli assessments cited by the newspaper said the withdrawal of Yemeni government forces from Perim, also known as Mayyun Island, at the entrance to the strait had significantly increased the Houthis’ ability to influence maritime traffic.

The development has raised concern in Israel over potential threats to commercial shipping through Bab el-Mandeb, which narrows to about 18 kilometers (11 miles) at some points.

Israeli assessments said the Houthis could use missiles and explosive-laden boats to target vessels transiting the strait.