The US says the measures are aimed at restricting the tribunal's resources and ability to operate.

Pillay is recognised for her "efforts to promote peace and international law", the Norwegian Nobel Committee says.

Truckloads of Eritrean soldiers have been seen driving into Ethiopia, which has reportedly responded with drone strikes.

The two works were seized last month when thieves cut through a fence and smashed a window at the Renoir Museum on the French Riviera.