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By Rocky Swift

TOKYO, June 19 (Reuters) - Japan's Nikkei share average

retreated from a four-month high on Thursday, as escalating

tensions between the United States and Iran dampened demand for

higher-yielding assets.

The Nikkei 225 Index closed 1% lower, snapping a

three-day winning streak that had pushed the gauge to the

highest since February 20. The broader Topix lost 0.6%.

The Israel-Iran conflict entered its seventh day, and U.S.

President Donald Trump was ambiguous about whether Washington

would join in bombardment of Iran's nuclear sites.

"Heightened tensions in the Middle East continue to cool

investor sentiment, with the downside appearing to widen," said

Nomura strategist Fumika Shimizu.

There were 62 advancers in the Nikkei index against 159

decliners. The largest percentage losses in the index were Trend

Micro ( TMICF ), down 8.4%, followed by Screen Holdings ( DINRF )

which skidded 4%.

Nippon Steel ( NISTF ) was among the top gainers, rising 2.3%

after completing its long-awaited $14.9 billion acquisition of

U.S. Steel.