Explosions and heavy machine gun fire are being heard across the Sudanese capital of Khartoum and troops are blocking roads leading to a sit-in camp of protesters who have demanded transition to civilian rule.

An Associated Press journalist also saw smoke rising from the site in Khartoum as the raid went on early Monday morning.

The sit-in has lasted weeks as civilians and military officials argue over the makeup of a transitional government.

The military overthrew longtime ruler Omar al-Bashir in April after mass protests against his 30-year rule.

Protesters insist no elections should be held before three years so that civilian leaders can dissolve all social and political networks of al-Bashir's old party and purge all state institutions.