The British pound was 0.37% higher to trade at $1.208, with the euro up 0.17% against the dollar at $1.1219.

"It has been a pretty quiet day overall. We have had sterling and euro bubbling up. I don't think there's any particular super-positive news behind that. But, markets held substantial shorts in both currencies," said Gregory Anderson, global head of foreign exchange strategy at BMO Capital Markets in New York.

The currency market is "heading into the deepest part of the holiday period. People are taking the shorts off and it puts upward pressure on both currencies. It's probably the biggest story in FX for today."

The dollar index <.DXY> was 0.1% lower at 97.390, having fallen earlier on expectations that a prolonged U.S.-China trade war would have a negative impact on American economic growth.

The Japanese yen rose to its highest against the dollar since March 2018 - barring a flash crash in January this year - as investors ramped up bets that the safe-haven currency could gain more if the trade conflict is prolonged. It was last 0.38% stronger against the dollar at 105.26.

"The stronger yen was at or near 2019 highs against its U.S. counterpart on prospects of a long drawn-out U.S.-China trade war. The longer the trade war drags on, the more likely it would weigh (on) the global outlook and crimp the world economy, a negative for market morale," said Joe Manimbo, senior market analyst at Western Union Business Solutions.

Goldman Sachs analysts on Sunday said they no longer expected Washington and Beijing to come to a trade agreement before the 2020 presidential election. They lowered their forecast for fourth-quarter U.S. growth and said the chances a protracted trade war would lead to recession were rising.

This week, market attention will be on Chinese retail sales and industrial output for July, due out on Wednesday, to gauge the trade war's impact on domestic activity.

Investors will also be focused on the U.S. Federal Reserve's annual symposium at Jackson Hole, Wyoming, later this month, seeking greater clarity on the future path of interest rates. Markets are expecting two to three additional rate cuts from the Fed by the end of the year.

(Reporting by Kate Duguid and Saikat Chatterjee; Editing by Paul Simao, Steve Orlofsky and Jonathan Oatis)

By Kate Duguid