ADEN, Yemen, Jan. 5 (Xinhua) -- An elderly woman and a child were killed and 16 others, mostly children, were injured in mortar shelling launched by Houthi rebels in Yemen's southwestern province of Taiz on Saturday, said a local official.

"The Houthis randomly shelled the 7th July neighborhood with mortar shells, leaving a woman and a child killed while 16 others injured mostly children," the official said on condition of anonymity.

All the injured were taken to a nearby hospital controlled by the government, he added.

A medical official in Taiz confirmed to Xinhua that some of the injured "were seriously injured."

Meanwhile, forces of the Saudi-backed Yemeni government and the Houthi rebels exchanged heavy shelling in the Red Sea port city of Hodeidah.

The escalating fighting coincided with the arrival of the UN special envoy to Yemen Martin Griffiths who is expected to meet with high-ranking Houthi leaders in the war-torn country.

Yemen has been mired in a civil war since late 2014 when the Houthi rebels overtook the capital Sanaa and ousted the government of President Abd-Rabbuh Mansour Hadi. A Saudi-led coalition has been fighting the Houthis since 2015.

The conflict has caused what the UN calls the world's worst humanitarian crisis, killing more than 10,000 people and with 14 million Yemenis now at the brink of mass starvation.