Russian President Vladimir Putin secured permission from his parliament on Saturday to use military force to protect Russian citizens in Ukraine, spurning Western pleas not to intervene.
Cash and U.S. gold futures hit four-month highs, while safe-haven currencies were also in vogue, with the Swiss franc touching its highest in over a year against the euro and the Japanese yen rising to one-month peaks versus the dollar.
In other markets, European equities fell and crude oil gained $2 a barrel as the United States threatened to isolate Russia economically in Moscow's biggest confrontation with the West since the Cold War.
Gold is usually seen as a hedge against oil-led inflation and tends to move in tandem with crude prices.
"Clearly, there is an ongoing shift in sentiment indicative of investors seeing some upside from geopolitical concerns, some safe-haven bids coming out of emerging markets and possibly a more neutral outlook towards equities," Mitsubishi Corp analyst Jonathan Butler said.
Spot gold rose as high as $1,350.00 an ounce in earlier trade, its loftiest since Oct. 30, and was at $1,343.26, up 1.4 percent, by 1054 GMT. It was headed for its biggest daily gain since Jan. 23.
Gold futures for April delivery hit a session high of $1,350.50 an ounce and later stood at $1,343.50, up $21.90.
The Group of Seven industrialised nations condemned Russia's intrusion into Ukraine and cancelled preparations for the G8 summit, which includes Russia, scheduled for Sochi in June, the White House said.
A recent series of weak U.S. data that showed how much a cold snap has hurt activity in the world's top economy, coupled with signs of a growth slowdown in China, boosted gold prices by 7 percent in February, the biggest monthly rise since July.
A U.S. nonfarm payrolls report on Friday should give investors a further opportunity to gauge the country's growth and its potential implications for the Federal Reserve's plan to unwind its stimulus programme.
HEDGE FUNDS INCREASE LONG POSITIONS
Hedge funds and money managers raised their net longs in gold futures and options to the highest in more than a year in the week to Feb. 25, data showed on Friday.
"We expect that so long as Ukraine/Russia tensions remain high, gold will remain bid but that needs to come from fresh longs as gross shorts are now much reduced," UBS said.
"The substantial increase in spec length in a relatively short span of time raises the potential for a short-term washout once geopolitical risks dampen."
The physical gold market got off to a slow start on Monday, with no signs of a pick-up in demand from jewellers. Premiums for gold bars in Singapore were unchanged from last week at 80 cents an ounce to spot London prices.
Silver followed gold's moves and rose 1.2 percent to $21.45 an ounce. Platinum was up 0.4 percent at $1,445.50 an ounce and palladium gained 0.6 percent at $743.60 an ounce.