UNITED NATIONS, March 26 (Xinhua) -- UN Secretary-General Antonio Guterres on Monday strongly condemned Sunday's missile attacks claimed by Yemeni Houthis toward Saudi Arabian cities, including the capital of Riyadh, said his deputy spokesman.

Guterres urged all parties to abide by their obligations under international humanitarian law to protect civilians and civilian infrastructure against attack, said Farhan Haq, the deputy spokesman.

The secretary-general called for restraint amid mounting tensions and stressed that military escalation is not the solution.

He emphasized that a negotiated political settlement through inclusive intra-Yemeni dialogue is the only way to end the conflict and address the ongoing humanitarian crisis.

Monday marks the third anniversary of the Yemeni civil war, pitting Houthi forces loyal to former President Ali Abdullah Saleh against forces loyal to the government of Abdrabbuh Mansur Hadi. In December 2017, conflict erupted between Houthi rebels and Saleh supporters, leading to the killing of Saleh.

The Saudi-led coalition, supported by the United States, is fighting the Houthi rebels.