U.S. and Japanese officials confirmed that the Treasury Department had moved last week to prop up the currency, which had been trading near four-decade lows.

By Makiko Yamazaki and Leika Kihara TOKYO, Aug 3 (Reuters) - Japan and the United States conducted coordinated yen-buying intervention and will not hesitate to take further action, Japan's finance ministry said on Monday,

The prolonged weakness of the yen, which recently hit a 40-year low against the dollar, has been a source of frustration in import-dependent Japan, where it has worsened inflation.

A major earthquake in Japan's southwest killed at least 13 people and left several injured or missing after a shopping center and a paper mill were heavily damaged.

Almost no other country in the world is rocked by such frequent and damaging earthquakes as Japan, which sits on the boundary of four tectonic plates.

The quake shook Japan's southern main island of Kyushu late Tuesday afternoon local time, causing damage and injuries.

A rarely used Federal Reserve liquidity facility could prevent the Japanese from selling Treasuries to prop up the yen, but prolonged use of the tool could encourage markets to test the US and Japan’s resolve,