BERLIN, Germany — German sportswear brand Puma nudged up its 2018 forecasts on Thursday after a jump in first-quarter results but the sportswear maker cautioned on volatile currencies and the threat of a U.S.-China trade war.

Puma reported a first-quarter operating profit of 112 million euros, up 60 percent, on currency-adjusted sales up 21 percent to 1.13 billion euros ($1.40 billion).

The advance in sales outpaced growth of 14.5 percent in the previous quarter.

Puma, which still lags German rival Adidas and market leader Nike, has revived its fortunes in recent years by spending heavily on sponsoring top soccer teams and partnering with celebrities such as singer Rihanna.

Puma shares were up 1.8 percent by 1048 GMT after the unscheduled announcement, making it one of the biggest gainers among German small-caps. Adidas was up 0.5 percent.

Puma said it now expects a 2018 operating profit of 310 million to 330 million euros, up from previous guidance of 305 to 325 million.

It sees sales at constant currencies rates rising by 10 and 12 percent, up from a previous target of 10 percent.

Puma also flagged new risks, however, citing volatile currency developments, political instability and trade tensions between China and the United States.

Last month, Puma announced plans to rejoin the basketball market as it makes a push to grow in the United States and China and bring its profitability closer to Adidas and Nike.

Puma is due to publish full results on April 24.

By Caroline Copley and Emma Thomasson; editors: Maria Sheahan and Jason Neely.