Alarm over Japan’s nuclear disaster grew yesterday, with more foreign governments advising citizens to flee Tokyo as army helicopters dumped water on the overheating plant at the center of the crisis.

Six days after a massive earthquake and tsunami plunged Japan into its worst crisis since World War II, the US and Britain chartered flights for nationals trying to leave and China moved thousands of citizens to Tokyo for evacuation.

Commercial airline tickets were scarce and some companies hired private jets to evacuate staff. In Tokyo, the streets were quiet but calm as the Japanese, though deeply concerned, mostly remained stoic over the emergency.