12 dead in blast near Yemen's Aden airport
"Twelve civilians were killed in an explosion" in the vicinity of Aden airport and "there are also serious injuries", said the official, who spoke on condition of anonymity, adding that the cause of the blast was unknown.
A spokesman from the Southern Transitional Council (STC) - part of Yemen's government - said the blast was caused by a car bomb explosion.
"A car bomb was detonated, killing a number of our peaceful citizens, including children, and wounding a number of other civilians," STC spokesman Ali al-Kathiri said in a statement.
The explosion comes almost three weeks after six people were killed in a car-bomb attack that targeted Aden's governor, who survived.
AFP footage on Saturday showed people pulling out a body from a vehicle that had been completely destroyed, as firefighters put out flames nearby.
The internationally recognised government relocated to Aden from the capital Sanaa in 2014, forced out by the Houthis, who are fighting Saudi-backed Yemeni government loyalists.
A Saudi-led military coalition intervened in Yemen's war in 2015.
No one has yet claimed responsibility for Saturday's blast, which is the deadliest in the area since December last year, when an attack targeting cabinet members ripped through Aden's airport.
At least 26 people, including three members of the International Committee of the Red Cross, were killed and scores were wounded when explosions rocked the airport as ministers disembarked from an aircraft.
All cabinet members were reported to be unharmed, in what some ministers charged was a Houthi attack.
Children killed in Taiz
Also on Saturday, three children were killed and three more were critically wounded in a neighbourhood of Yemen's third city Taiz, by what state media said was rebel mortar fire.
"The Iranian-backed Houthi militia targeted the Al-Kamp neighbourhood with... shells, which led to the death of three children," the Saba new agency said.
One of the wounded children has had his legs amputated and all three "are in a critical condition", it added.
A security official told AFP that the three children killed were brothers.
A doctor at Taiz hospital confirmed the report to AFP, and said the toll could rise.
Taiz is a city of 600,000 people under government control in the southwest of Yemen, a country that has been at war for the last seven years.
In recent weeks, fighting has intensified around the government's sole remaining northern stronghold - the city of Marib in the oil-rich province of the same name.
The coalition has said it has killed a total of some 2,000 rebels around the city in almost daily strikes since October 11.
Yemen is also home to Al-Qaeda in the Arabian Peninsula, which launches periodic attacks against both fighters aligned with the country's authorities and the insurgents.
Tens of thousands of people, mostly civilians, have been killed and millions displaced in Yemen's conflict, which the United Nations has called the world's worst humanitarian crisis.