A massive blackout cut power to as many as 580,000 households for a short period in central Tokyo on Wednesday afternoon, disrupting trains and traffic lights and bringing elevators to a halt.

The blackout hit houses and office buildings in 11 of Tokyo's wards, including Minato, Chiyoda and Shinjuku, but most of them had supplies restored within 10 minutes.

Tokyo Electric Power Company Holdings Inc. said the outage was likely caused by the fire at a Tepco facility in Niiza, Saitama Prefecture.

Later in the day, the utility held a news conference and apologized for the trouble. "The site is surrounded by a fence, and we believe (the problem) was not caused by a third-party intrusion," a company official told reporters.

Economy minister Hiroshige Seko directed the utility to investigate the cause of the problem, and to take further actions to prevent any recurrence.

As firefighters tackled the blaze, videos posted on Twitter showed thick black smoke billowing from the ground and flashes of flame. The smoke was so dense that it resembled that of rubber burning.

The municipal office advised residents not to open their windows. An official of the city of Niiza said cables at the Tepco facility had caught fire.

The blaze was adjacent to National Route 254, which was closed to traffic.

Many restaurants and shops line the road in the vicinity of the blaze, but the area is located far from residential zones, according to the Niiza official.

According to the website of Seibu Railway Co., 11 lines operated by the firm were suspended or suffering delays as of 7:06 p.m.

Information from Kyodo added