United Nations :Former UN chief Kofi Annan urged the Security Council on Friday to push for the return to Myanmar of hundreds of thousands of Muslim Rohyingas who have been driven out in an army campaign. Annan, who led an advisory commission to the Myanmar government, said world powers must work with the country’s military and civilian leaders to end the refugee crisis. More than 500,000 people, mostly Rohingyas, have since late August crossed into Bangladesh, fleeing military operations in Myanmar’s Rakhine state that the United Nations has denounced as ethnic cleansing. Myanmar authorities say they are rooting out Rohingya militants following attacks on police posts in late August. The issue of the return of the Rohingyas is shaping up as a major hurdle. A recent report by the UN human rights office accused Myanmar of seeking to permanently expel the Rohingya, by planting land mines at the border with Bangladesh.