Japan Prime Minister Naoto Kan sorry for nuclear mix-up
Japan's prime minister has apologised for causing confusion by ordering nuclear firms to carry out safety tests on their reactors, weeks after his government said the plants were safe.
Naoto Kan said his order for "stress tests" on Wednesday came too late.
Local officials and energy firms say they no longer know whether they can restart their reactors or not.
Two-thirds of Japan's reactors have remained inactive since the devastating earthquake and tsunami on 11 March.
The 9.0-magnitude earthquake and tsunami levelled towns along the country's north-east coast, leaving thousands homeless and killing more than 14,000 people.
The disaster also wrecked the Fukushima Daiichi plant, causing radiation leaks and a national review of nuclear power.
After carrying out inspections, ministers announced last month that the country's nuclear plants were safe to reopen.
But in a surprise announcement on Wednesday, the government said stress tests were needed - giving no timescale and few details of what the tests would entail.
The mayor of the southern town of Genkai, who had already given his consent for the local power station to be restarted, held an angry news conference on Thursday denouncing the government's U-turn.
On Friday, Shikoku Electric Power announced it was postponing plans to restart two reactors at Ikata because it did not believe it could get public support.
Other local officials and power firms have appealed to the government to clarify its policy.
Mr Kan told a cabinet meeting on Friday he was sorry, saying: "My instruction was inadequate and came too late."
His chief cabinet secretary Yukio Edano acknowledged that the government needed to be clearer.
"We realise that we need to clarify the situation, but right now we are discussing exactly what the next step will be," he said.
The government has said it was satisfied that Japan's plants were safe, but the stress tests were designed to allay people's fears.
Mr Kan has been under huge pressure over his handling of the nuclear crisis and the reconstruction of areas devastated by the tsunami and earthquake.