SANAA, Yemen -- An airstrike by the Saudi-led coalition targeting Yemen's Shiite rebels and their allies struck a poor residential area in the capital of Sanaa on Monday, killing 25 civilians and wounding at least 50, according to the rebels and medical officials.

The strike hit the slums of the Sawan neighbourhood in eastern Sanaa early in the morning, said the rebels, known as Houthis.

Smoke billowed from the struck area in Sawan, which is located just hundreds of metres from a military camp used by the rebels. Hospital officials said there were women and children among the casualties.

Airstrikes also hit other parts of Sanaa and 10 Yemeni provinces on Monday, according to local officials.

The strikes and ground fighting in Yemen have continued for the third day since the start of a UN-brokered truce between the rebels and the country's internationally-backed government in exile and its allies. The Saudi-led coalition has said it is not bound by the truce because of a lack of commitment by the Houthis.

In New York, the United Nations said Secretary-General Ban Ki-moon was disappointed that the humanitarian pause he called for did not take hold, but that he has not lost hope that a suspension in the fighting could still take place.

"Obviously the secretary-general is very, very much disappointed," UN spokesman Stephane Dujarric said Monday. "We've not lost hope and the discussions are ongoing."

In Sawan, several buildings were partially destroyed and ambulances were seen ferrying the wounded while rebel gunmen cordoned off the area. Ahmed Nasser, a resident who lives nearby said he heard the explosion and stayed indoors, fearing more strikes.

Yemen's conflict pits the Iran-allied Houthis and troops loyal to former President Ali Abdullah Saleh against an array of forces, including southern separatists, local and tribal militias, Sunni Islamic militants as well as loyalists of exiled President Abed Rabbo Mansour Hadi, who is backed internationally.

On the ground, security officials said clashes continued between the Houthis and their rivals in the cities of Aden and Taiz. Fighting also resumed between the two sides in Marib, according to military and tribal officials.

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

The Saudi-led coalition launched the airstrikes campaign in March against the Houthis, who seized Sanaa and other parts of the country. More than 3,000 people have been killed in Yemen since the strikes began and as the ground fighting continues.