(Corrects to show oil prices rose, not fell, in headline)

SINGAPORE (Reuters) -Israel has begun carrying out strikes on Iran, two U.S. officials said, adding there was no U.S. assistance or involvement in the operation. The officials, who spoke on condition of anonymity, declined to provide further information.

Financial markets reacted, with U.S. stock futures down more than 1%, oil prices jumping and U.S. Treasury prices up.

QUOTES:

KARL SCHAMOTTA, CHIEF MARKET STRATEGIST, CORPAY, TORONTO:

"Traders are scurrying for safety as reports of a strike on Iran cross the wires, but details on the scale and magnitude of the attack remain scarce and moves have been relatively limited thus far."

CHARU CHANANA, CHIEF INVESTMENT STRATEGIST, SAXO, SINGAPORE:

"The geopolitical escalation adds another layer of uncertainty to already fragile sentiment.

"The key question now is whether this marks a brief flare-up or the beginning of broader regional escalation. If the situation de-escalates quickly, markets may retrace some of the initial moves. But if tensions rise - particularly with any threat to oil supply routes - the risk-off mood could persist, keeping upward pressure on crude and haven assets."

(Reporting by Reuters markets team)