Immigration authorities are taking measures against 177 people who have either overstayed their visas or arrived in Japan illegally after a series of raids on premises in Tokyo’s Kabukicho district this month, Tokyo Regional Immigration Bureau authorities said Saturday.

While authorities have already begun preparations to deport the detained individuals, firms that employed the workers are unlikely to face criminal charges, immigration authorities said.

“Since the intent of the search was to cleanse the environment of the area, it probably won’t come to that (charges against employers),” a Tokyo Regional Immigration Bureau official said.

Employers of illegal aliens are punishable by a maximum of three years’ imprisonment and 2 million yen in fines.

The illegal workers were located in two separate sweeps of a total of 12 bars and nightclubs in Shinjuku Ward. The first sweep, on May 16, identified 149 illegal aliens working in eight bars and was Japan’s largest capture of illegals in a single search, officials said.

The majority of those detained were women working as hostesses, officials said.

In all, 127 South Koreans, 26 Chinese, 19 Filipinos, four Thais and one Malaysian were caught. A total 113 had overstayed their visas while 17 had entered the country illegally.

Of those caught, 135 are being detained and will be deported, officials said. The remaining 42 are still being questioned.

The searches were made after a series of tip-offs from the public in April, officials said.

One person detained in the sweeps had overstayed his visa for 12 years, officials said.

The Justice Ministry’s Immigration Bureau estimates there were 268,421 overstayers in Japan as of July 1, 1999, a 10.1 percent decline from the peak estimate made in May 1993 of 298,646 individuals.