TOKYO >> The operator of the crippled nuclear power plant leaking radiation in northern Japan announced a plan Sunday to bring the crisis under control within six to nine months and allow some evacuated residents to return to their homes.

But officials stressed the roadmap for ending the crisis at the Fukushima Dai-ichi nuclear power plant was only a first step, that conditions remain unstable, and that it remains unclear when the government will let evacuees go back.

Prime Minister Naoto Kan, facing pressure both at home and abroad to resolve Japan’s worst-ever nuclear power accident, directed Tokyo Electric Power Co. to draw up the plan.

“Given the conditions now, this is best that it could do,” said Hidehiko Nishiyama of the government’s Nuclear and Industrial Safety Agency. “But it cannot be said that the reactor has stabilized.”

The roadmap, presented by TEPCO Chairman Tsunehisa Katsumata at a news conference, includes plans to cover the damaged reactor buildings to contain radiation and eventually remove the nuclear fuel.

“We sincerely apologize for causing troubles,” Katsumata said. “We are doing our utmost to prevent the crisis from further worsening.”

The company is focusing first on cooling the reactors and spent fuel pools and reducing the level of leaking radiation, decontaminating water that has become radioactive, reducing the amount of radiation released into the atmosphere and soil, and lowering radiation levels in the evacuation area, he said.

In the next stage, it aims to firmly control the release of radioactive materials, achieve a cold shutdown of the reactors and temporarily cover the reactor buildings, Katsumata said.

Frustrations have been mounting over TEPCO’s failure to resolve the nuclear crisis more than a month after a catastrophic earthquake and tsunami hit Japan on March 11, knocking out power and cooling systems at the Fukushima Dai-ichi complex.

Evacuees who have been forced to abandon their homes, jobs and in many cases their farms were unconvinced by TEPCO’s plan.

“I don’t believe a word they say,” said Yukio Otsuka, 56, a private school owner whose home is about 5 kilometers (3 miles) from the facility.

Goshi Hosono, an adviser to the prime minister and member of his nuclear crisis management task force, said he understood that people might be frustrated by the timeline.

But he added, “There is no shortcut to resolving these issues. Though it will be difficult, we have to go step by step to resolve these problems one by one.”

Katsumata, who was hammered by questions over his managerial responsibility, told reporters he was considering stepping down because of the crisis.

“I feel very responsible,” he said.

Trade Minister Banri Kaieda said some evacuees might be able to return home within six to nine months. He urged TEPCO to beat that deadline, though it is clear the full cleanup will take years.

In a show of support for a staunch American ally, U.S. Secretary of State Hillary Rodham Clinton expressed admiration and sympathy for the Japanese as she visited Tokyo on Sunday.

Clinton met with Kan, the prime minister, and had tea with the emperor and empress, who have been visiting evacuation centers to show their sympathy and support for the victims of the disasters, which have left nearly 28,000 people dead or missing.

“We pledge our steadfast support for you and your future recovery. We are very confident that Japan will demonstrate the resilience that we have seen during this crisis in the months ahead,” Clinton said.

She said Matsumoto told her Japan hoped for U.S. feedback on TEPCO’s plan.

Kan said in a weekend commentary in the International Herald Tribune that ending the nuclear crisis as soon as possible was his “top priority.”

As Japan has begun planning for reconstruction and mulling how to pay for it, Kan’s political opponents have resumed calls for his resignation after refraining from criticism in the immediate aftermath of the disaster.

Government officials fanned out across the affected areas over the weekend seeking to explain evacuation decisions and calm nerves. Chief Cabinet Secretary Yukio Edano met Sunday with the governor of Fukushima, who has vigorously protested the predicament the nuclear crisis poses for his prefecture.

“The safety of residents is our foremost priority,” Edano said. “I told the governor that the government will do everything it can to prevent the crisis from worsening.”

Explosions, fires and other malfunctions have hindered efforts to repair the stricken plant and stem radiation leaks.

TEPCO Vice President Sakae Muto said Sunday the Unit 2 containment vessel at the plant was leaky and likely to have been damaged, but added that the spent fuel roads in the cooling pool in Unit 4 were confirmed not to have been damaged, which could have greatly complicated containment efforts.

Workers have been spraying massive amounts of water into the overheated reactors and spent fuel storage pools. Some of that water, contaminated with radiation, has leaked into the Pacific.

Officials reported late Saturday that radioactivity had again risen sharply in seawater near the plant, signaling the possibility of new leaks. Authorities have insisted the radioactivity will dissipate in the ocean and poses no immediate threat to sea creatures or people who might eat them. Most experts agree.

Regardless, plant workers began dumping into the sea sandbags filled with sand and zeolite, a mineral that absorbs radioactive cesium, over the weekend to reduce radiation levels.

TEPCO said it plans to establish a system to recycle cooling water that will remove radioactivity as well as salt left behind by seawater that was earlier used as an emergency cooling measure. Salt corrodes the reactors and interferes with the cooling system.