Saudi Arabian ground troops have entered northern Yemen to prevent Houthi rebels from consolidating their forces. "Saudi ground forces seized control of two areas in Saada province and intend to advance toward Houthi positions," military sources told Anadolu, according to Haberler. The Saudi incursion, the first ground offensive in Yemen since coalition began its military campaign in March, is aimed at preventing attacks by Houthi rebels on its territories.

Saudi military spokesperson, Brigadier General Ahmed Assiri, said Wednesday that their ground troops have taken some Houthi-held territories under their control, according to Press TV. Assiri, however, said the invasion was a temporary military strategy and not aimed at gaining territories in Yemen.

The Saudi invasion came a day after Houthi rebels launched a Scud-type ballistic missile targeting an electricity power station in the southern Saudi province of Jizan, according to Yemen's Saba news agency.

Houthis, loyal to former President Ali Abdullah Saleh, control a large part of Yemen -- including the capital Saana -- while ousted President Abu Mansur Hadi is in exile in Saudi Arabia and heading Yemen's internationally recognized government.

The Yemeni government-in exile said it would not negotiate with Houthi rebels unless they gave up their arms. "The Houthis and Saleh's militias must implement the U.N. resolution and surrender their weapons, and only then the dialogue and political process can begin, with the participation of all Yemeni parties," Yemen's Foreign Minister Riad Yassin said Thursday, according to Associated Press.

A U.S.-supported Saudi-led coalition of nine Arab nations has been carrying out airstrikes against Iran-backed Houthi Shia militia in Yemen since March.

Global rights body Human Rights Watch (HRW) has called on Saudi Arabia to stop its use of cluster bombs against Yemen. "The loss of civilian life in Hajja shows why most countries have made a commitment never to use cluster munitions," Ole Solvang of HRW said in a statement on Wednesday. "These weapons not only kill or injure people at the time of attack, but the unexploded submunitions go on killing long afterward."