Fighting has been fiercest in southwestern Yemen, near the Bab el-Mandeb Strait and around Taiz, where the Houthis are trying to encircle government forces. (EPA Images pic)

RIYADH: Saudi-backed Yemeni government forces seized key positions on the Bab el-Mandeb Strait on Monday, military and government sources said, as they fought to reverse last month's advances by the Iran-backed Houthis and drive them from the vital waterway.

The government forces have taken large parts of Dhubab district, which overlooks Bab el-Mandeb, and are asserting full control over the area with heavy air support from a Saudi-led coalition, three military sources and one government source told Reuters.

Houthi-aligned media had earlier denied that government forces had made advances in the area.