Houthi rebels have shelled Yemen's state television offices in Sanaa as they push into the capital, forcing hundreds of residents to flee out of fear of an escalation of violence, according to local officials.

The Shia rebel group clashed with the army on the northwestern outskirts of Sanaa, shutting down international flights to the main airport on Friday.

In a statement carried on the state news agency SABA, the civil aviation authority said foreign airlines had suspended flights to Sanaa airport for 24 hours, after which they would review the security situation.

Battles erupted a day earlier between the Houthis and fighters loyal to the Islah party, the Muslim Brotherhood's branch in Yemen.

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The two sides fought in Shamlan, a suburb of Sanaa that is home to the Islamic Iman University, an institution seen as a breeding ground for Sunni rebels.

Al Jazeera's Hashem Ahelbarra, reporting from Sanaa on Thursday, said the rebels were in total control of the Shamlan and Wadi Dhahr districts on the capital's outskirts, and were moving towards the heart of the city.

The advance by the Houthis comes after weeks of unrest in Sanaa, where the Houthis have blocked the road to the main airport and staged anti-government sit-ins at ministries.

At least 50 people have also been killed in clashes involving Houthi fighters in different parts of the country since Tuesday.

The fighting has further destabilised an impoverished country also struggling to overcome a secessionist movement in its south, the spread of an al-Qaeda insurgency and other threats.

Source: Al Jazeera and agencies