The MSCI All-World index was last down 0.l%, led by declines in Europe, where defence stocks weighed on the Stoxx600, which fell 0.3%.
Gold, often perceived as a safe haven in times of geopolitical or market turmoil, rose 0.6% to $1,932 an ounce.
Brent crude futures rose 0.5% to $74.26 a barrel, having earlier fetched as much as $74.80. The rouble dropped by as much as 3% to a 15-month low earlier in Moscow.
Russian mercenaries mounted a short-lived rebellion on Saturday, seizing the southern city of Rostov and advancing on Moscow demanding the removal of Russian military commanders in charge of the war in Ukraine.
The armed mutiny over the weekend by the powerful Wagner group and its abrupt ending with no apparent penalties for the perpetrators or their leader was followed on Monday, 26 June, by official moves to return the country to normal.
The consequences for Russia's 16-month-old invasion of Ukraine were not clear, though the challenge to Putin's authority was the starkest in decades of his leadership.
With little in the way of concrete cues for markets, investors stuck to their recent playbook of favouring fixed income and other safe havens over equities, particularly in light of Friday's slew of weak business activity surveys.
"The market is still in this kind of transition phase, but I think the stress that we've seen in equity markets started before the news we got on Friday and before the events over the weekend," said Frederik Ducrozet, head of macroeconomics research at Pictet Wealth Management.
"My guess would be that, when in doubt, you just follow the trend over the last few days and you will soon be facing this hawkish vibe from Europe and the central banks," he said.
Gold, which had hit a three-month low on Friday, rose 0.5% to $1,932 an ounce. US Treasuries were firm with yields, which fall when prices rise, edging down for a second day.
Two-year yields fell 5 basis points to 4.70%. Ten-year yields slipped 6 bps to 3.685%.
"This (Russian) putsch ... has revealed cracks and fragilities that now cannot be unseen," said Mizuho economist Vishnu Varathan. "It undeniably amplifies global geopolitical risks."
Defence stocks such as BAE systems and France's Dassault Aviation were among the biggest negative weights on the European stock market. In the US pre-market, Lockheed Martin and Northrop Grumman shares were both down 0.8%.
Adding to the sense of unease across markets were the latest travel figures for last week's holiday in China that were not as strong as expected, again highlighting how the post-Covid recovery in the world's second largest economy is fading.
S&P Global also followed most Wall Street banks and cut its 2023 GDP growth forecast for China on Sunday.
Last week, another round of central banks, including the Bank of England and those of Norway and Switzerland, added to the chorus of voices calling for higher interest rates to wrestle inflation lower.
The S&P 500 staged its biggest one-week drop in three months last week and e-mini futures pointed to another decline at the open later, down 0.2%.
In currencies, the euro was flat against the dollar at $1.091, up 0.14% against the pound at 85.78 pence, but down 0.4% against the yen .
European markets showed little reaction to Greece's conservative New Democracy party storming to re-election victory on Sunday. Greek 10-year bond yields fell 5 bps to 3.55%, while stocks in Athens eased 0.6%.
The Ifo institute said its business climate index, and Klaus Wohlrabe, the head of Ifo surveys, said in an interview on Monday, 26 June, the German economy faces the likelihood of a more protracted recession.
The yen, which has fallen nearly 9% this year as global interest-rate expectations rise and Japan's central bank stays dovish, bounced as much as 0.5% to below 143 per dollar, partly thanks to speculation around intervention or a policy shift.