Safe-haven bonds and the yen jumped in Asia on Friday, while stocks fell after the United States launched cruise missiles against an air base in Syria, raising the risk of confrontation with Syrian backers Russia and Iran.
The US dollar dropped three-quarters of a yen in currency markets, while sovereign bonds, gold and oil prices rallied hard.
MSCI's broadest index of Asia-Pacific shares outside Japan shed 0.7 per cent in short order, and S&P 500 futures lost 0.5 per cent in an unusually sharp move for Asian hours. Japan's Nikkei was stripped of its early gains to slip 0.1 per cent.
US President Donald Trump has ordered the strikes against a Syrian air base controlled by President Bashar al-Assad's forces in response to a deadly chemical attack in a rebel-held area, a US official said.
Facing his biggest foreign policy crisis since taking office in January, Trump took the toughest direct US action yet in Syria's six-year-old civil war.
Investors had already been on edge as Trump met Chinese leader Xi Jinping for talks over flashpoints such as North Korea and China's huge trade surplus with the United States.
“While President Trump had flagged a response to this week's chemical attack in Syria, the swiftness of the response and the willingness to take action halfway through the Trump-Xi meeting caught markets a little off-guard,” said Sean Callow, senior currency strategist at Westpac in Sydney.
“There should be limited market follow-through, however, with no indication at this stage that this is the start of a broad-based, sustained US military campaign.”
It was not yet clear if this strike would be the only one, though Secretary of State Rex Tillerson did say the attack was "proportionate".
Yen, dollar
The yen, a favoured haven in times of stress due to Japan's position as the world's largest creditor nation, climbed across the board. The dollar fell to 110.30 from 110.95 just before news of the attacks hit dealing screens.
The dollar was otherwise unscathed, however, as it benefited from flows into safe-haven US Treasuries. Against a basket of currencies it was barely lower, while the euro held steady at $1.0649.
Yields on 10-year Treasury debt fell five basis points to 2.29 per cent, breaking a significant chart barrier at 2.30 per cent for the first time this year.
Crude oil, gold
Spot gold prices jumped 1.2 per cent to $1,266.01 an ounce and touched their highest since November 10.
“Clearly this raises the stakes, and we expect to see gold prices continuing to push higher in the short term, at least until there is some clarity around whether this is a one-off or develops into something more,” ANZ analyst Daniel Hynes said.
Oil also caught a bid on concerns the military intervention could affect supplies from West Asia.
US crude jumped 93 cents to $52.63 a barrel, the highest in a month, while Brent added 90 cents to $55.79.