Spot gold was up 0.3% at $1,420.70 per ounce as of 0555 GMT, after hitting its lowest since July 17 at $1,413.80 in the previous session.
U.S. gold futures were steady at $1,420.80 an ounce.
"We have geopolitical tensions in Iran, and also we remain very cautious and sceptical about the (U.S.-China) trade negotiations expected to begin next Monday, because plenty of things remain unsolved between the two nations," said Margaret Yang Yan, a market analyst at CMC Markets.
"On the other side, the dollar index is rallying which is having a negative impact on gold prices."
Uncertainty in the Middle East continued as a U.S. Navy ship took defensive action against a second Iranian drone in the Strait of Hormuz last week, but did not see the drone go into the water, the U.S. military said on Tuesday.
On the trade front, a report said U.S. Trade Representative Robert Lighthizer would travel to Shanghai next week for meetings with Chinese officials to hammer out a deal to end the long-drawn trade tussle between the world's top two economies.
The dollar index extended gains to a five-week high, making gold expensive for holders of other currencies.
The European Central Bank is likely to at least offer a nod to easier policy at its meeting on Thursday, while the U.S. central bank is widely expected to lower interest rate at its meeting ending July 31.
Futures remain 100% priced for a rate cut of 25 basis points (bps) from the Federal Reserve next week, and even imply an 18% chance of 50 basis points.
"If the Fed does a 25 bp rate cut next week, I don't think gold prices will feel any stronger as it has been already priced in," said Howie Lee, economist, OCBC Bank.
"But if the Fed surprises with a 50 bp cut, that might push gold prices to test the $1,450 level."
Meanwhile, holdings of SPDR Gold Trust, the world's largest gold-backed exchange-traded fund, fell 0.25% from Monday to 823.13 tonnes on Tuesday.
Spot gold looks neutral in a narrow range of $1,412-$1,427 per ounce, and an escape from the range could suggest a direction, said Reuters technical analyst Wang Tao.
Among other precious metals, silver rose 0.5% to $16.48 per ounce.
Platinum gained 0.6% to $859 an ounce, while palladium eased 0.3% at $1,523.