The Yemeni aviation authorities on Wednesday closed the International Sanaa Airport, suspending all departing flights and diverting incoming planes to other airports due to the intensification of street clashes between government forces and gunmen of a powerful opposition tribal leader.

"International Sanaa Airport suspended all arriving and departing flights on Wednesday as incoming planes of Sanaa were diverted to airports in southern the country, such as Aden airport and others," an official of the aviation authorities told Xinhua.

He said on condition of anonymity that the step came "upon directions from the Yemeni political leadership."

Intensified clashes continued in the capital Sanaa for three consecutive days as forces of the Republican Guards blocked all entrances of the city to prevent large numbers of armed tribesmen from joining the militants of opposition leader Sadiq al-Ahmar, according to an officer of the Republican Guards.

However, several fierce clashes took place in a number of Sanaa's entrances during the day between forces of the Republican Guards and tribesmen who were on their way to Sanaa to support al- Ahmar's militants, leaving many dead from both sides, a government official said.

The forces fired heavy weapons to drive armed tribesmen back, the official said, requesting anonymity.

Street battles which have been taking place in downtown Sanaa since Monday have so far left 79 people from both the armed rivals dead, according to a Xinhua toll count based on medic and official sources.