WASHINGTON 

President Joe Biden offered US support for Japan in the wake of powerful earthquakes on Monday which left four people dead. 

"My administration is in touch with Japanese officials, and the United States stands ready to provide any necessary assistance for the Japanese people," said Biden in a statement.

"As close Allies, the United States and Japan share a deep bond of friendship that unites our people. Our thoughts are with the Japanese people during this difficult time," he added.

An earthquake with a preliminary magnitude of 7.6 rocked a wide area on the Sea of Japan coast Monday, killing at least four people, followed by a series of smaller quakes.

Many houses collapsed and railway services were temporarily suspended in some areas of Japan.

Prime Minister Fumio Kishida called on the public to be alert for more powerful tremors, while authorities urged residents living near the coasts to evacuate to safer areas.

The quake also triggered a tsunami alert, but authorities downgraded it hours later, the Kyodo news agency reported.