OSAKA -- NTT West Corp. on Tuesday suspended connection services to a company in Fukuoka that allegedly made "wangiri" phone calls in such massive numbers that it threatened to paralyze NTT's telephone networks, NTT West officials said.

The Nippon Telegraph and Telephone Corp. unit said it has cut off services of 10 lines contracted to the company.

It is the first such move since contract revisions were made Aug. 2 empowering NTT firms to suspend service for up to six months to unscrupulous subscribers in cases where they may disrupt phone networks, such as by "deliberately making a massive number of calls" that are intended to go unanswered.

The suspension is to remain in effect until the company promises in writing to stop making the one-ring calls.

In a wangiri scam, the caller hangs up after one ring, leaving a phone number on the display of the receiving party's handset in hopes the receiving party dials the number.

NTT West said it detected a massive number of calls by the firm at around 8 a.m. Monday and temporarily suspended services to the firm after an hour due to worries that phone networks would be paralyzed during a resumption of normal business activities after the end of the Bon holidays.

NTT West monitored the company after services resumed at about 8 p.m. Monday but found the firm again making massive calls beginning at around 10 p.m.

NTT officials said they decided to halt service at around midnight on the grounds the firm's bulk calls were deliberate and might disrupt phone networks.

The Fukuoka company registered with NTT West under the same name as a firm in Osaka that received a warning on July 30 for making more than 2,000 wangiri calls in three minutes.

The Osaka company said it acknowledged NTT's warning but did not promise to stop making the bulk calls, according to NTT West.

Massive influxes of calls from another Osaka firm have paralyzed phone networks in Osaka and Hyogo prefectures on occasions over the past two months.

The term wangiri derives from combining the word one, pronounced "wan," and "kiru," to cut off.

Those who are tricked into returning the call are usually connected to a taped phone sex message or information on other types of adult entertainment, and those who stay on the line are often charged hefty fees.

The revisions to NTT contracts also alow turning down applicants considered potential wangiri operators.