Yemen's third largest city of Taiz was seized by Shia Houthi militia on Sunday, media reported.
The city is located between the capital Sanaa and the southern city of Aden, BBC reported.
According to officials, Houthi fighters dressed in military uniform could be seen arriving at the airport and patrolling parts of the city.
Dozens of tanks and military vehicles could be seen heading from north Yemen towards Taiz.
Yemen has been in conflict over the past few months, since Houthis took over the capital of Sanna and President Abdrabbuh Mansour Hadi fled to the southern port city of Aden.
The rebels declared a new government in February and said a transitional five-member presidential council would replace President Hadi.
