Dozens of Vietnamese who gathered for an anti-China protest in central Hanoi were taken away by authorities Sunday as they tried to rally support for an international tribunal's ruling rejecting Beijing's claims in the South China Sea.

About two dozen people were bused away from around the landmark Hoan Kiem Lake in the capital even before they began their protest. There was heavy police presence around the lake with cars briefly banned from around it.

The rally was organized by No-U group in Hanoi, which opposes China's expansive claims in the South China Sea. It came after The Hague-based Permanent Court of Arbitration last week issued the ruling in a case initiated by the Philippines, which together with Vietnam is one of the claimants in the disputed waters.

Vietnam's Communist authorities have clamped down on such protests before, fearing they could stir dissent.

China rejected the tribunal's ruling and refused to take part in the arbitration.

The U.N. tribunal ruled that China violated international maritime law, specifically the Philippines' maritime rights by building up artificial islands that destroyed coral reefs and by disrupting fishing and oil exploration.