NATO Secretary-General Jens Stoltenberg talks to the media outside Downing Street after a meeting with Britain's Prime Minister Boris Johnson in London, Britain October 15, 2019. REUTERS/Henry Nicholls

LONDON (Reuters) - NATO is concerned about the consequences of Turkey’s military operation in northeastern Syria on the fight against Islamic State, Secretary General Jens Stoltenberg said on Tuesday.

“I’m concerned about the consequences for the gains we have made in fighting our common enemy Daesh,” he told reporters.