SANAA, April 9 (Xinhua) -- Visiting UN Special Envoy to Yemen Martin Griffiths on Tuesday extended his condolences to the victims' families of Sunday's explosion in the Yemeni capital Sanaa that killed 13, including seven schoolgirls.

In a statement, Griffiths called on the warring sides to put an end to the suffering of Yemeni civilians and allow young Yemenis to grow up in peace.

The envoy offered his sincere condolences to those "affected by this tragic loss of life" in Sawan area in Sanaa on April 7, he said.

"I strongly urge all parties to make every possible effort to put an end to civilian suffering and allow young Yemenis to grow up in peace and safety. Only an inclusive political solution will end this cycle of violence and destruction," Griffiths added.

On Sunday, the United Nations said on its website that the explosion in a warehouse in Sawan, east of Sanaa, killed at least 13 civilians, including seven schoolgirls, and wounded more than 100 others.

The Houthi rebels, who control Sanaa, accused the government-allied Saudi-led coalition of carrying out an airstrike on Sawan quarter. However, the coalition denied conducting any operation on the area on that day.

The warehouse is located few meters from two schools. The rebels prevented journalists from reaching the site following the explosion.

Griffiths arrived on Monday in Sanaa to push the rebels for implementing a stalled peace deal they agreed upon in Stockholm in December last year.

Griffiths met Abdulmalik al-Houthi, the chief of the rebel group, on Monday evening to discuss the crisis, according to the group spokesman Mohammed Abdulsalam.

Griffiths has been shuttling between the Iranian-allied Houthi rebels in Sanaa and the Yemeni government in the Saudi capital Riyadh to end over four years of civil war, which erupted after the rebels seized much of the country's north in late 2014.