At least 20 rebels and pro-government fighters have been killed in Saudi-led coalition air strikes targeting insurgent positions in south Yemen, military sources said on Tuesday.

The raids struck the rebel-held headquarters of the 19th Infantry Brigade and checkpoints in Baihan, a region between the provinces of Shabwa which is government-held, and oil-rich Marib which both sides are fighting to control.

Over the past 24 hours, 17 rebels were killed in strikes that also "mistakenly" left three pro-government fighters dead, the sources said.

The coalition, which began its air campaign against Iran-backed rebels in late March in support of exiled President Abedrabbo Mansour Hadi, has backed government loyalists with both weapons and troops.

Loyalists have seized five southern provinces, including Shabwa, since mid-July and have been advancing towards the capital Sanaa which has been held by the rebels for almost a year.