TOKYO - The operator of Japan's quake-hit nuclear plant said on Sunday it aims to reduce radiation leaks within three months and achieve a "cold shutdown" within six to nine months.

Tsunehisa Katsumata, chairman of Tokyo Electric Power Co (TEPCO), said at a news conference on Sunday that the company aims to start reducing radiation from the explosion-charred facilities at the Fukushima Daiichi plant within three months.

And within six to nine months, TEPCO said in a statement, it expects to cool all the six reactors in a "cold shutdown", a stable condition in which temperatures drop to 100 C and radiation leaks fall dramatically.

TEPCO's plan is composed of three projects including cooling reactors and the fuel pool, avoiding further release of radioactive substances and monitoring the surrounding environment.

"As the short-term targets, we have set two steps," said Katsumata. "Step one is to steadily reduce the amount of radiation.

"In step two, we aim to control the release of radioactive substances and greatly control the amount of radiation."

"There are various risks ahead," he added. "But we aim to complete step one in about three months and step two in another three to six months."

TEPCO offered the timeline to end the crisis more than five weeks after the massive earthquake and tsunami knocked out cooling systems at its six-reactor Fukushima plant.

Radiation has since leaked into the air, soil and sea from the coastal plant northeast of Tokyo.

Katsumata again apologized and said the company would do its utmost to allow evacuated residents to return home. He also revealed that he and Masataka Shimizu, the company's president, are considering stepping down from their posts.

On the same day as TEPCO released its roadmap, Japanese Minister of Economy, Trade and Industry Banri Kaieda said that he hoped to confirm as early as possible areas free of radioactive risk to keep people forced to leave their homes informed of when they could go back.

Visiting Tokyo, US Secretary of State Hillary Clinton vowed full support for earthquake-hit Japan on Sunday to revitalize a sometimes-uneasy alliance.

"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," she said after meeting Foreign Minister Takeaki Matsumoto.

Clinton and Matsumoto said that they were launching a business partnership to support Japan's reconstruction on its northeastern coast, where 13,705 people have been confirmed dead and more than 14,000 are still missing.

AFP-AP-China Daily