(Updates with closing prices)

TOKYO, June 13 (Reuters) - Japan's Nikkei share average

fell on Friday as investors sold riskier assets after Israel

launched widescale strikes against Iran, stoking worries about

geopolitical risks.

The Nikkei fell 0.89% to close at 37,834.25,

mirroring moves in U.S. stock futures, but posted a 1.14% gain

for the week.

The broader Topix fell 0.95% to 2,756.47 and

gained 0.5% for the week.

"The market was selling stocks on caution for geopolitical

risks, but the news was not driving a fire sale because

investors still wanted to monitor the development of the

attacks," said Naoki Fujiwara, a senior fund manager at Shinkin

Asset Management.

Israel launched strikes against Iran on Friday, saying it

targeted nuclear facilities, ballistic missile factories and

military commanders, and that this was the start of a prolonged

operation to prevent Tehran from building an atomic weapon.

Chip-making equipment maker Tokyo Electron ( TOELF ) fell

4.8%, dragging the Nikkei the most. Uniqlo-brand owner Fast

Retailing ( FRCOF ) lost 1.61%.

Exporters fell as the yen strengthened, with Toyota Motor ( TM )

and Nissan Motor ( NSANF ) falling 2.35% and 1.26%,

respectively.

Energy sectors rose as oil prices jumped. Oil explorers

jumped 2.77% to become the top performer among the

Tokyo Stock Exchange's 33 industry sub-indexes.

Oil refiners gained 1.61% and the utility sector

gained 1.17%.

Defense-related shares also rose, with Mitsubishi Heavy

Industries ( MHVYF ) and IHI rising 2%, respectively.

Of more than 1,600 stocks trading on the TSE's prime

market, 17% rose and 79% fell, with 2% trading flat.