* U.N. says relocation of staff will not effect work in Syria
* Situation worsens in Syria, impunity widespread -U.N. official (Adds comment from World Food Programme, detail)
UNITED NATIONS, March 25 (Reuters) - The United Nations will move about half of its 100 foreign staff out of Syria after mortar bombs fell near their hotel in Damascus, damaging the building and a U.N. vehicle, the United Nations said on Monday.
U.N. spokesman Martin Nesirky said another 800 local U.N. staff had been asked to work from home until further notice.
"The United Nations Security Management Team has assessed the situation and decided to temporarily reduce the presence of international staff in Damascus due to security conditions," Nesirky said.
Syrian rebels lobbed mortar bombs into central Damascus on Monday, killing at least two people and drawing a fierce army response as bombardments shook the capital.
"The United Nations remains active and committed to helping the Syrian sides in their search for a political solution," Nesirky said. "U.N. agencies and partners also remain committed to providing assistance to millions of people in need in Syria."
The two-year conflict began as peaceful protests that turned violent when Syrian President Bashar al-Assad tried to crush the revolt. The United Nations says more than 70,000 people have been killed and nearly 1.2 million have fled the violence.
Nesirky said mortar bombs had landed on the grounds of the hotel in Damascus housing U.N. staff on Sunday and Monday.
He said the international staff worked for peace mediator Lakhdar Brahimi, the resident U.N. coordinator, the U.N. children's agency UNICEF, the Office for the Coordination of Humanitarian Affairs, the World Food Programme and the United Nations Relief and Works Agency for Palestine Refugees, UNRWA.
"There will still be in country enough people to be able to continue and indeed to increase the range of work, particularly to reach people with food aid," Nesirky said.
World Food Programme (WFP) Executive Director Ertharin Cousin said the agency's work would not be affected.
"WFP is working right now to reach 2 million people by the end of March, and ... 2.5 million by the end of April, and we will continue to maintain the staff that are necessary to achieve these goals," she said.
The U.N. Security Council has been deadlocked on Syria since 2011. Russia and China have refused to consider sanctions on Assad's government and have vetoed three resolutions condemning his crackdown on opposition groups.
U.N. Special Coordinator for the Middle East Robert Serry briefed the 15-member Security Council on Monday and said the situation in Syria was continuing to worsen.
"The continuing pursuit of a military victory by both sides and their reckless disregard for civilian lives and their protection are of deep concern for the United Nations," he said. "Impunity is widespread, human suffering and destruction are pervasive."
The United Nations said on Thursday it would investigate Syria's allegations that rebel forces used chemical weapons in an attack near Aleppo, but Western countries are seeking a probe of all claims concerning the use of such banned arms.
U.S. and European officials say there is no evidence of a chemical weapons attack. If one is confirmed, it would be the first use of such weapons in the Syrian conflict. (Reporting by Michelle Nichols and Louis Charbonneau at the United Nations and Emma Batha in London; Editing by Doina Chiacu and David Brunnstrom)