UNITED NATIONS, Dec. 23 (Xinhua) -- UN Undersecretary-General for Humanitarian Affairs Mark Lowcock on Monday condemned the attacks over the weekend on the premises of three international humanitarian organizations in Yemen.

The attacks by unknown individuals in the early hours of Saturday and Sunday in Al Dhale in southwest Yemen represent an alarming escalation in the risks faced by humanitarian workers in the war-torn country, Lowcock said in a statement.

Twelve organizations have now been forced to suspend aid programs in Al Dhale, which will affect 217,000 locals. Several organizations are working with local staff to ensure the most essential activities can continue, he said.

"I condemn these attacks unreservedly. I urge a thorough investigation, and I express my appreciation to the government of Yemen for the work they have begun in this regard."

He also voiced grave concern over the continuation of media campaigns in parts of Yemen that spread rumors and incitement against aid operations.

Humanitarian agencies reach more than 12 million people every month in Yemen and rely on the authorities to ensure a safe, enabling environment for humanitarian operations across the country, said Lowcock.

The attacks over the weekend wounded one person and damaged property.