Sendai, Japan (AP) - A tsunami warning issued after a magnitude-7.1 aftershock rattled Japan has been lifted.
The warning was in place for only about an hour. The aftershock shook buildings and briefly forced Tokyo's main international airport to close both of its runways, but there have been no immediate reports of damage or injuries.
The warning came as Japan observes the one-month anniversary of the massive wave that killed as many as 25,000 people.
The epicenter of Monday's aftershock was just inland and about 100 miles (160 kilometers) north of Tokyo.
The operator of the crippled Fukushima Dai-ichi nuclear complex says the latest quake briefly cut power but it was quickly restored. Operations there are not endangered.
THIS IS A BREAKING NEWS UPDATE. AP's earlier story is below.
SENDAI, Japan (AP) -- A strong earthquake rattled Japan's northeast Monday and sparked a fresh tsunami alert on the one-month anniversary of the massive temblor and wave that devastated the northeastern coast and unleashed a still-unfolding nuclear crisis.
The 7.1-magnitude aftershock briefly forced Tokyo's main international airport to close both of its runways. The epicenter was just inland and about 100 miles (160 kilometers) north of Tokyo. The operator of the crippled Fukushima Dai-ichi nuclear complex said the latest quake had no impact on the plant.
A warning was issued for a three-foot (one-meter) tsunami, the same as for after an aftershock that shook the northeast coast last week. That quake generated no tsunami.
People at a large electronics store in the northeastern city of Sendai screamed and ran outside, though the shaking made it hard to move around. Mothers grabbed their children, and windows shook. After a minute or two, people returned to the store.
There were no new reports of damage. Aftershocks have repeatedly rattled the disaster-weary region, but there is little left in the northeast to ruin. Last Thursday's 7.1-magnitude aftershock, which had been the strongest tremor since the day the original quake hit, did sink hundreds of thousands more households into darkness, however. Most of that electricity has been restored.
The 9.0-magnitude earthquake and the tsunami it generated on March 11 are believed to have killed more than 25,000 people and caused as much as $310 billion in damage. The nuclear power plant they disabled has been spewing radiation since, and even a month on, officials say they don't know how long it will take to cool reactors there.