Residents of two more towns near Japan’s stricken nuclear power plant have begun evacuating amid radiation concerns, but officials said Monday that the plant’s three damaged nuclear reactors will still likely be stabilized and closed in six to nine months, as planned.

“We believe we can stick to the current timeframe,” said Goshi Hosono, the prime minister’s aide and nuclear crisis task force director, reports the Associated Press. “What’s crucial is how we can proceed with cooling,” he said. “Even though the cores had melted, they are somewhat kept cool.”

The initial closure timelines, set out in April, came under scrutiny last week when new data showed that the Unit 1 reactor at the Fukushima Dai-ichi nuclear complex had been more damaged than previously know. The government acknowledged the reactor’s fuel rods had mostly melted after the March 11 earthquake and tsunami knocked out the plant’s cooling system.

On Monday, in a bit of good news, authorities said the temperature inside the reactor core has fallen to nearly 100 Celsius (212 F), a level considered safe and close to a cold shutdown, according to AP. Hosono said a similar meltdown had probably occurred at Units 2 and 3, because they were both out of water for more than six hours after the March 11 power outage. He said Unit 1 was without water for more than 14 hours.

The plant, operated by the Tokyo Electric Power Co., is still leaking radiation and contaminated water. That prompted the government in late April to order residents of two more towns, Kawamata and Iitate, to vacate their homes, which they began doing this weekend. The 6,700 people remaining in the two areas, which are outside the previous 12-mile (20-kilometers) radius evacuation zone, are expected to leave by the end of June.