The biggest supplier of aid to rebel-controlled eastern Ukraine says its mission could fold in two days' time if rebels continue to block its convoys.

A charity foundation owned by Ukraine's richest man, Rinat Akmetov, has been the largest source of aid for the separatist-controlled territory while international organizations were having difficulty to deliver any aid across the front line. Since the Ukrainian government stopped paying pensions and benefits in the region last year, Akhmetov's aid has been virtually the only lifeline for the most destitute there.

But the foundation said on Monday rebels have been blocking their convoys for 10 days and if they keep doing it, the foundation would have to shut its distribution points in the east as early as Wednesday.