SANAA — At least 13 people were killed on Tuesday in the first air strikes by a Saudi-led coalition on the Yemeni capital in five months, residents said, as the head of the U.N. expressed concern about the escalation in the fighting.

Fighting has intensified since U.N.-sponsored peace talks between the Houthis, backed by forces loyal to former President Ali Abdullah Saleh, and the internationally recognized government ended on Saturday without an agreement.

Medics put the death toll at 13. Most of the casualties were women working at the al-Aqel potato chip factory in the Nahda district of the capital.

Residents said the factory was inside an army maintenance camp that had been hit by repeated air strikes since fighting began in March last year.

The Houthi-run news agency has put the death toll at seven, including five women, and said 13 people were injured.

Residents and local Yemeni media also reported air strikes in the Red Sea port city of Hodeida and other parts of Yemen.

The Saudi-led coalition is backing Yemeni forces loyal to the government of President Abd-Rabbu Mansour Hadi, who are trying to oust Iran-allied Houthi forces from the capital, Sanaa. Hadi was forced to flee Yemen to Saudi Arabia as Houthi forces advanced on his headquarters in Aden in March 2015.

United Nations Secretary-General Ban Ki-moon said he was concerned about the reports of increased fighting, a U.N. spokesman said on Tuesday, but added the world body was unable to independently verify reports of civilians deaths.

Saudi Arabia intercepted two ballistic missiles fired at the kingdom by the Houthi movement on Wednesday, Saudi-owned Al Arabiya TV reported.