Today in Pictures: Dec. 20

A Yemeni tribesman from the Popular Resistance Committee, supporting forces loyal to Yemen's Saudi-backed President Abedrabbo Mansour Hadi, fires a weapon as a fellow tribesman rescues the body of a dead comrade in the country's third-city of Taez during clashes with Shiite Huthi rebels, on December 19, 2016.

An Afghan officer reacts in front of a burning pile of seized narcotics and alcoholic drinks, in the outskirts of Kabul, Dec. 20, 2016.

South African surfer Grant Baker drops in on a large wave during the Nazare Challenge championship at Praia do Norte in Nazare, Portugal.

An aerial view from a drone shows smoke billowing from the San Pablito Market, where an explosion ripped through a fireworks market in Tultepec, Mexico. Sirens wailed and a heavy scent of gunpowder lingered in the air after the afternoon blast at the market, where most of the fireworks stalls were completely leveled. According to the Mexico state prosecutor there are dozens dead.

Indian Sikh participants perform 'Gatka' the Sikh martial art during a competition in Amritsar on December 20, 2016. Gatka, is a traditional South Asian form of combat-training, developed by Sikhs, in which wooden sticks are used to simulate swords in sparring matches. Other weapons are not used for full-contact sparring, but their techniques are taught through forms training. The ritual form is purely for demonstration and is performed to music during occasions such as weddings.

A man places his hand over his mouth as he walks past graffiti of a dragon on a street in Beijing. Thick, gray smog fell over Beijing, choking China's capital in a haze that spurred authorities to cancel flights and close some highways in emergency measures to cut down on air pollution.

A young displaced Iraqi boy, who fled the Islamic State stronghold of Mosul, sits in a wheelbarrow at Khazer camp, Iraq.

Worshippers gather around a huge incense burner as they offer their prayers at the Sensoji Buddhist temple in the Asakusa district of Tokyo.

Kashmiri fishermen cover their heads and part of their boats with blankets and straw as they wait to catch fish in the waters of the Anchar Lake on a cold day in Srinagar.

People light candles at a makeshift memorial in front of the Kaiser-Wilhelm-Gedaechtniskirche (Kaiser Wilhelm Memorial Church) in Berlin, where a truck crashed the day before into a Christmas market. Twelve people were killed and almost 50 wounded, 18 seriously, when the lorry tore through the crowd on Dec. 19, smashing wooden stalls and crushing victims, in scenes reminiscent of July's deadly attack in the French Riviera city of Nice.