The U.N. Security Council on Friday called on Libya to release four detained International Criminal Court staff members.

Cairo - At least four people were killed on Wednesday in renewed clashes between two rival ethnic groups in a remote Libyan town, according to a military official.

Ten were injured in the fighting that shattered a shaky truce between the Arab Zwai and the African Tebu groups in the south-eastern town of Kufra, Libyan newspaper Al Watan reported online, citing the head of the town's military council.

The Tebu felt discriminated under the 42-year rule of the now-slain Libyan leader Muammar Gaddafi.

The clashes first broke out between the two groups 10 days ago, raising concerns about security in post-Gaddafi Libya.

Last week, the Defence Ministry dispatched troops to Kufra, where they brokered a ceasefire that has been repeatedly violated since.

Five citizens of Chad, believed to be involved in the fighting, were arrested in Kufra on Tuesday, reported Al Watan.

In recent months, Libya has witnessed periodic clashes between former rebel forces who were united in ousting Gaddafi.

At least six people died in January when two rival militia groups clashed in the centre of the capital Tripoli. - Sapa-dpa