United Nations, April 11 (IANS): The humanitarian situation is getting worse by the hour in Yemen, said a UN spokesman Friday.

According to the World Health Organization(WHO), violence killed 643 people and injured 2,226 between March 19 and April 6, Xinhua quoted UN spokesman Stephane Dujarric as saying in a daily briefing here.

Heavy clashes were reported in Aden, a seaport city in Yemen and an unknown number of health workers and volunteers in Aden, including staff of a Yemeni NGO, were abducted by parties to the conflict and taken to unspecified locations, he said.

The status of the hostages is unknown, and concerns are mounting for their well-being, said the spokesman.

Johannes Van Der Klaauw, the UN Humanitarian Coordinator for Yemen, called on all the parties for an immediate humanitarian pause in this conflict so that humanitarian organizations and personnel can safely deliver assistance to the most vulnerable Yemeni people, according to the spokesman.