Houthis rebels and their allies advanced in the heart of Yemen's second city Aden in heavy fighting that killed at least 20 people, medical and security sources said on Tuesday.

A Saudi-led coalition meanwhile pressed air strikes for a seventh straight day since announcing a halt to its bombing campaign last Tuesday, an AFP correspondent and witnesses reported.

The rebels and their allies have lost 200 dead to the strikes since they began on March 26, a spokesman said, accusing the coalition of escalating not ending its air war.

In Aden, forces loyal to exiled President Abedrabbo Mansour Hadi were pushed back in the city's central Khor Maksar district as the rebels overran Hadi's family home and the German and Russian consulates, a local official said.

Nine rebels were killed in the fighting, a source close to them said.

Eleven dead were brought into government-run hospitals, the city's health chief Al-Khader Lasswar said, without specifying whether they were pro-Hadi militiamen or civilians.

Hadi fled to neighbouring Saudi Arabia when the rebels closed in on Aden last month and the southern port city has seen fierce fighting ever since.

The rebels have received crucial support from army units still loyal to former president Ali Abdullah Saleh, who was forced from power in 2012 after a bloody year-long uprising.
Their bases have been one of the main targets of the Saudi-led air campaign and one in the heart of the rebel-held capital Sanaa was hit before dawn on Tuesday, an AFP correspondent reported.

Witnesses also reported air strikes on the rebels and their allies in oil-rich Marib province, east of the capital, around third city Taez, and in the Red Sea port of Hodeida.

A spokesman for the pro-rebel armed forces said that 112 soldiers, 43 policemen and 45 Houthis militia had been killed in five weeks of coalition air strikes.

In a statement carried by the rebel-controlled Saba news agency late Monday, Brigadier General Sharaf Luqman accused Riyadh of "moving into a new stage" of its air war, not halting it as promised.

The rebels have said they will not return to UN-brokered peace talks until the air strikes end.