Saudi-led coalition warplanes have launched fresh air strikes on Yemen's capital, Sanaa, after Yemen's Houthi rebels fired two ballistic missiles against military targets in Saudi Arabia.

At least 13 people have reportedly died in the airstrikes. Fighting in Yemen has intensified since UN-sponsored peace talks between Houthi militants and Yemen's internationally recognised government ended on Saturday.

The UN says more than six thousand and four hundred people, mostly civilians, have been killed in Yemen since Saudi Arabia's coalition air campaign began last March.