- Traders aggressively bought the dollar against the British pound and the Canadian dollar.
- U.S. President Donald Trump said there was no need to keep Canada in NAFTA.
- Trump also threatened to withdraw from the World Trade Organization if "they don't shape up."
The dollar held near a one-week high on Monday amid concern about global trade after U.S.-Canada trade negotiations reached an impasse.
Traders aggressively bought the dollar against the British pound and the Canadian dollar. The dollar's status as the chief reserve currency make the U.S. currency the primary beneficiary of concern over trade conflicts.
On Saturday, U.S. President Donald Trump said there was no need to keep Canada in the North American Free Trade Agreement and warned Congress not to meddle with the trade talks or he would terminate the trilateral pact altogether.
But gains were muted - safe-haven currencies such as the Swiss franc and the Japanese were supported against higher-yielding rivals.
"Trade tensions are broadly supporting the dollar, but the market is hardly very conducive of risk," said Viraj Patel, an FX strategist at ING in London.
In early London trading, the dollar edged higher to 95.22, nearing its highest level since Aug. 27 against a basket of its rivals. It has gained nearly 7 percent since mid-April when trade tensions first arose.
The euro weakened 0.1 percent against the dollar after Fitch Ratings left its credit rating for Italy unchanged at "BBB" but revised its outlook to negative on Friday.
Sterling was the biggest loser against the dollar after the European Union's chief Brexit negotiator, Michel Barnier, said he is "strongly opposed" to the British government's proposals on future trade ties after it leaves the EU.
Trading was quiet with U.S. markets shut for a holiday and before European manufacturing PMI data due shortly