TOKYO - Japan's Nikkei share average ended lower on Wednesday, as deeper tensions in the Middle East left investors with little appetite for riskier assets while markets awaited further developments.

The Nikkei extended losses to slide 2.18% to an over one-week closing low of 37,808.76, while the broader Topix finished 1.4% lower at 2,651.96.

Iran launched ballistic missiles on Tuesday, spurring vows from Israeli Prime Minister Benjamin Netanyahu that its arch foe would pay for the attack. Tehran said any retaliation would be met with "vast destruction", raising fears of a wider war.

"The escalation in the Middle East has resulted in a classic risk-off reaction, posing headwinds for broader Japanese equities," said Charu Chanana, global market strategist and head of forex strategy at Saxo.

Japanese technology shares led losses, following their U.S. peers lower after a nearly 3% drop on the Philadelphia SE Semiconductor index overnight.

Wall Street's three main stock indexes also ended lower on Tuesday, with the Nasdaq losing more than 1%, as a risk-off mood spread following news of Iran's attack.

Chip-related shares Tokyo Electron and Advantest slipped 3.7% and 4.8%, respectively, while AI-focused startup investor SoftBank Group fell 2.4%.

Defence-related stocks, which were among the few gainers in early trade, were sold off, including Kawasaki Heavy Industries down 0.6%.

Of the index's 225 constituents, 187 ended in the red.

Uniqlo parent firm Fast Retailing shed nearly 4% to weigh the heaviest in the Nikkei.

Bucking the trend, energy shares were supported by a jump in oil prices on fears that the Middle East conflict could disrupt supply. Inpex was up 4.41% to top the index's percentage gainers.

Oil and coal producers were among the best performers by sector, with a 2.2% jump, just behind miners that advanced 4.3%.

(Reporting by Brigid Riley; Editing by Tom Hogue, Rashmi Aich and Sherry Jacob-Phillips)