United Nations, January 9 (RHC)-- UN Secretary General Ban Ki-moon has expressed concern over Saudi Arabia’s intensifying airstrikes against civilians in Yemen, warning that Riyadh’s use of cluster bombs in the capital, Sanaa, may amount to a “war crime.”

UN spokesman Stephane Dujarric told reporters on Friday that Ban is “deeply concerned” about Saudi Arabia’s intensification of airstrikes in residential areas and on civilian buildings in the Yemeni capital, including the Chamber of Commerce, a wedding hall and a center for the blind, “despite repeated calls for a renewed cessation of hostilities.”

He added that the UN chief has also received “troubling reports” that cluster munitions have been used against civilians in many locations in Sana’a. "The use of cluster munitions in populated areas may amount to a war crime due to their indiscriminate nature," the UN spokesperson pointed out.

At least one Yemeni civilian was killed and a number of others were injured after Saudi jets pounded various districts of Sanaa, using cluster bombs early on Thursday. Saudi warplanes also bombarded residential buildings in the al-Marzaq district of Hajjah Province, killing four people and injuring two others.