Switzerland froze the assets and bank accounts of nine more Ukrainians, including another son of ousted president Viktor Yanukovich and the son of a former prime minister, all of whom are suspected of human rights abuses and misuse of state funds.

The European Union, Britain, Switzerland and others have already frozen assets of Ukrainians suspected of misappropriating state funds, after Yanukovich was toppled following months of demonstrations against a decision to spurn a free trade deal with the EU for closer ties with Russia.

On Monday, Swiss officials widened their measures to include Yanukovich's son, also called Viktor, and Oleksii Azarov, son of the former prime minister, Mykola Azarov.

Oleksander Yakymenko, the former head of the security service, and Artem Pshonka, the son of Ukraine's former prosecutor general, are also on the Swiss list, which took effect earlier on Monday.

Ukraine's new prime minister, Arseny Yatseniuk, has said Yanukovich embezzled as much as $37 billion during three years in office.

Yanokovich's elder son, Oleksander, owns Mako Group, a Ukrainian conglomerate with a Swiss arm that was raided by Geneva prosecutors last month.