The government of South Sudan says it has sacked 40 of its overseas diplomats after they failed to show up for work.In a memo, the South Sudanese foreign ministry said they had been on unauthorised leave for months or even years.It said that after fruitless attempts to contact and persuade them to return to work in the capital, Juba, it had no option but to fire them.The statement said some diplomats had been posted to embassies in the United States and Britain, other in missions in Uganda and Kenya.In the last three years, Juba has closed and downsized embassies due to the economic damage caused by five years of conflict.Nearly 400,000 people have been killed and a third of its population displaced.