World stock markets fell Tuesday as investors worried about a possible U.S. military strike against Syria over its suspected use of chemical weapons.
European indexes and most major Asian markets fell, while U.S. stock futures were more than 0.5% weaker ahead of the open. German government bonds and gold were firmer as investors sought less risky assets, and concern about the regional implications sent oil prices higher in Europe.
Investors have grown increasingly concerned that the U.S. and its allies are preparing for military action against Syria ever since Secretary of State John Kerry's speech Monday that evidence "strongly indicates" chemical weapons were used in Syria.
A spokesman for U.K. Prime Minister David Cameron told reporters Tuesday that the British military was making "contingency plans" for a strike on Syria.
Related: Military strikes likely response?
Kerry's comments condemning Syria were interpreted as a war speech, sparking a downward move in the Dow Jones industrial average and S&P 500 during the final hour of trading on Monday. It also erased modest gains in the Nasdaq, which closed flat.
All major European markets fell in morning trading as overseas investors fretted about how the U.S. will react to the Syrian situation. Germany's DAX and France's CAC 40 both fell by about 1.5%.
Looking ahead to daily economic data, the Conference Board will publish its monthly report on consumer confidence at 10 a.m.
Shares of jewelry retailer Tiffany & Co (TIF) rose in premarket trading after the company reported better-than-expected quarterly results.
Shares in struggling department store operator J.C. Penney (JCP) fell on news that activist shareholder Bill Ackman is selling his entire stake of more than 39 million shares.
Asian markets ended with mixed results Tuesday. Both Japan's Nikkei and Hong Kong's Hang Seng fell by as much as 0.7%, but the Shanghai Composite edged up by 0.3%.
In Australia, shares in surfwear maker Billabong plunged after it posted a huge loss and wrote off the entire value of its brand.