NEW YORK (Reuters) - The United Nations is 'deeply concerned' about the safety and protection of tens of thousands of people in Afghanistan's Lashkar Gah who could be trapped by fighting between government forces and the Taliban, a U.N. spokesman said on Wednesday.

       The Taliban have stepped up their campaign to defeat the U.S.-backed government since April as foreign forces complete their withdrawal after 20 years of war.

       "Since the start of the year nearly 360,000 people have been forcibly displaced by the conflict in Afghanistan. About 5 million people have been displaced since 2012," U.N. spokesman Stephane Dujarric told reporters.

       Fighting has been particularly heavy around the city of Herat, near the western border with Iran, and Lashkar Gah and Kandahar in the south.

       "We're deeply concerned about the safety and protection of people in Lashkar Gah, in the south, where tens of thousands of people could be trapped by the fighting," Dujarric said.

       He also said in Helmand and Kandahar "there are reported increased civilian casualties, destruction or damage to civilian houses, as well as to critical infrastructure and hospitals."

       (Reporting by Michelle Nichols; Editing by Paul Simao)