FILE PHOTO: European Trade Commissioner Cecilia Malmstrom attends a panel discussion at the United Nations in Geneva, Switzerland June 4, 2018. REUTERS/Denis Balibouse

GENEVA (Reuters) - European Union Trade Commissioner Cecilia Malmstrom said in a tweet on Friday that she was worried about the tit-for-tat tariff hikes between the United States and China, and warned about where the escalation was leading.

“Worrying development with escalation of tariffs between U.S. and China. Clearly damaging for the world economy. Trade wars are bad and not easy to win,” she wrote.