* Yuan drops below 7 per dollar
* Wall Street tumbles on renewed trade worries
* Yen, bonds and gold benefit
* Oil down as trade war concerns hit demand outlook (Updates with U.S. market action, changes byline, dateline from previous LONDON)
By Saqib Iqbal Ahmed
NEW YORK, Aug 5 (Reuters) - Stock markets around the world fell hard and the Chinese yuan weakened to an 11-year low on Monday as fears of an escalation in the U.S.-China trade war jolted financial markets.
China on Monday let the yuan tumble beyond the key 7-per-dollar level for the first time in more than a decade, in a sign Beijing might be willing to tolerate further currency weakness in the face of an escalating trade row with the United States.
Safe-haven assets, including the Japanese yen, government bonds and gold rallied as investors sought to cut back on riskier assets.
"I think there's a sense that President Trump might try and escalate in terms of a reaction, if he thinks that this was a deliberate move by the Chinese to try and weaken their currency artificially,” said Brian Daingerfield, head of G10 fx strategy for the Americas at NatWest Markets in Connecticut.
Against the Japanese yen, which investors tend to buy in times of risk aversion, the U.S. dollar fell 0.38% to its lowest since a January flash crash.
The sharp moves in financial markets come after U.S. President Donald Trump stunned investors last week by vowing to impose 10% tariffs on the remaining $300 billion of Chinese imports from Sept. 1, abruptly breaking a brief month-long ceasefire in the bruising trade war.
On Monday, MSCI's All Country World Index, which tracks shares in 47 countries, extended its slide from last week to dip 1.89% on the day, close to a two-month low.
On Wall Street, the main indexes fell sharply led by technology companies.
"Trade continues to trend in the wrong direction," said Ryan Detrick, senior market strategist for LPL Financial in Charlotte, North Carolina.
"Any hopes of a quick resolution with China are fading quickly."
The Dow Jones Industrial Average fell 489.78 points, or 1.85%, to 25,995.23, the S&P 500 lost 55.68 points, or 1.90%, to 2,876.37 and the Nasdaq Composite dropped 200.40 points, or 2.5%, to 7,803.67.
The pan-European STOXX 600 index fell 2.13%, putting it on pace for its largest two-day decline in over three years.
Worries about a slowdown in global growth due to an extended trade conflict hurt oil prices.
"The escalation of trade measures only reinforces concerns over global economic growth and hence by extension global oil demand growth," said Harry Tchilinguirian, global oil strategist at BNP Paribas in London.
Brent crude futures were down $1.53, or 2.47%, to $60.36 per barrel, while U.S. West Texas Intermediate (WTI) crude futures were down 0.97 cents, or 1.74%, to $54.69 a barrel.
Concerns about the outlook for trade lifted gold to a more than six-year high on Monday. Spot gold was up 1.12% at $1,456.55 per ounce.
U.S. Treasury yields tumbled on Monday with 10-year yields hitting their lowest level since November 2016, as fears over escalation of trade U.S.-Chinese tensions renewed concerns about an economic downturn, spurring safe-haven demand for bonds.
The yields on benchmark 10-year Treasury notes were down 8.8 basis points at 1.7667%.
Reporting by Saqib Iqbal Ahmed; Additional reporting by Karen Brettell in New York, Noah Browning in London, and Medha Singh and Arjun Panchadar in Bengaluru Editing by Susan Thomas