Japan, under pressure from international groups, said Thursday that it will increase monitoring and consider issuing new evacuation orders as potentially dangerous radiation levels spread farther from the Fukushima Daiichi nuclear power plant.

At the same time, monitoring concerns arose for workers at the stricken plant when its owner, Tokyo Electric Power Co., said it does not provide a personal radiation-monitoring device to every worker.

Further signs of spreading contamination and hazardous working conditions surfaced Thursday as Kyodo News reported radioactive iodine 10,000 times above the legal limit in groundwater near the unit 1 reactor at the facility.

Earlier, the International Atomic Energy Agency reported that Iitate, a village 25 miles northwest of the power plant, posted radiation levels “about two times higher” than levels at which it recommends evacuations.

The mandatory evacuation zone extends only 12 miles around the stricken plant, although the government has encouraged people within 18 miles to evacuate voluntarily.

Japan’s chief government spokesman, Yukio Edano, said the government will heed the United Nations nuclear agency’s advice and step up its monitoring. “If the situation continues, there can be health risks, so we will take necessary actions depending on the results of these surveys.”

By Friday, government officials said radiation levels in Iitate remained within Japan’s safety standards. They attributed the confusion to differences in sampling and international thresholds for evacuation. The IAEA measures contaminants in the soil, and Japan uses atmospheric levels when making decisions about evacuation.

Nearly three weeks after a tsunami flooded the reactors’ cooling systems, triggering hydrogen explosions and partial nuclear meltdowns, traces of radioactive fallout have been tracked across the globe.

The Japanese government is churning out spreadsheets on radiation levels in the air, ocean and soil. Numbers are broadcast like weather reports in some cities and have informed bans on exporting vegetables, the evacuation limits and no-fishing zones.

Increasingly, those numbers arebeing scrutinized and second-guessed by residents of Japan, who fear the invisible isotopes and are skeptical of official safety assurances. Scores of international advocacy groups and university researchers are descending on the troubled region to monitor the impact of the disaster.

Foreign governments are also getting involved, pledging help to improve Japan’s monitoring. The U.S. Navy will send a 140-member radiological control team to aid in the battle against nuclear fallout, Gen. Ryoichi Oriki, Japan Self-Defense Force chief, said at a news conference. The Navy’s “radcon” team already had a 21-member unit stationed aboard the USS Ronald Reagan to assess the radioactivity levels on aircraft.

And French President Nicolas Sarkozy met with Prime Minister Naoto Kan and pledged more technical assistance. A team of French engineers is working with Tepco.

Four robots from Reston-based QinetiQ are also on the ground in Japan, with company workers training Tepco employees Thursday. The Virginia company also sent two kits to remotely operate Bobcat loaders. The driverless construction vehicles “can be used for debris clearance, taking supplies downrange, hose pulling. There are a lot of attachments,” said QinetiQ President J.D. Crouch II.

At the center of the evacuation zone, working conditions at the nuclear plant have become extremely dangerous, with multiple highly radioactive areas. The critical job of removing contaminated water that has pooled in basements and in underground tunnels is moving slowly, in part because radiation levels are so high.

Nuclear safety experts say radiation-shielding clothing and a dosimeter that can track exposure are a minimum safety standard. But Tepco told Japanese national broadcasting company NHK on Thursday that its supply of radiation-monitoring equipment is limited.

Despite government regulations that require each worker to wear a dosimeter, a company official said that in some of the plant’s less radioactive areas, only group leaders are given one. Some workers have said publicly that they are concerned about whether their exposures are being measured.

In response to the outcry, Tepco officials said Friday that they will slow work so that every worker can wear one.

Radioactive iodine levels found 1,000 feet offshore climbed to a record high Thursday for the second consecutive day, this time measuring 4,385 times the legal safety limit.

Although government officials said that even the higher levels should not have adverse health effects, the finding reaffirmed fears of continuous leaks from damaged reactor cores.

Iitate’s vice mayor, Shinichi Monma, said Thursday that village officials are not fazed by the radiation reports from the international groups. “We still respect and follow the Japanese government’s information and orders,” Monma said.

On Thursday night, town officials lifted a ban on consuming tap water that has been in place since March 21; they said the levels no longer exceed safety limits. The ban will stay in place for babies up to a year old.

But Yasumitsu Sato, 68, reached at his store, where he sells wood to contractors, said the reports of unsafe radiation levels have renewed his fears and compounded his frustration with the government’s lack of information.

“All they say is to stay at home and nothing more,” he said.

Sato left the village for a few days, along with many of his neighbors, but he had to return because he could not afford to stay away from work. He wants to leave again, this time with a government order, so he can be assured of shelter, food and health care.

“I have all the necessary items: valuables, food, water . . . filled up in the car, and I am ready to leave at once,” he said.

Staff writer David Nakamura and special correspondent Tetsuya Kato contributed to this report from Tokyo. Staff writer Brian Vastag contributed from Washington.