A man walks at the site of a Saudi-led air strike that hit a residential area last month near Sanaa airport, May 18, 2015. [Photo/Agencies]

SANAA -- Fighter jets of a Saudi-led coalition bombed military sites controlled by Yemen's Shiite Houthi group and former republican guards in capital Sanaa on Tuesday, one day after a five-day truce expired.

Witnesses said the warplanes hit missiles depots on Faj Attan Mountain in western Sanaa that is controlled by the Houthis and forces loyal to former President Ali Abdullash Saleh.

Fire and smoke resulting from a series of powerful explosions could be seen from downtown Sanaa.

The warplanes also hit Houthi-controlled military sites on Nokm mountain in eastern Sanaa, according to military sources.

Residents in the western port city of al-Hodayda also saw air strikes on Houthi military sites in the Red Sea city.

The fresh air strikes came hours after the Houthis handed over to the International Committee of the Red Cross the body of a Moroccan pilot, whose plane was shot down in the Houthi stronghold of northern Saada province on May 10.

On Monday, the Saudi-led alliance resumed its air raids against Shiite Houthi group in the southern port city of Aden shortly after the truce expired late Sunday, according to army sources.

The warplanes targeted the presidential compound and Aden airport, both controlled by the Houthis, and several Houthi military gatherings in the port city.

United Nations envoy to Yemen Ismail Ould Cheikh Ahmed urged all warring parties to extend the humanitarian cease-fire at a conference held in the Saudi capital of Riyadh. He said the truce should be turned into permanent cease-fire to end all acts of violence.