LONDON - British Prime Minister Boris Johnson and NATO Secretary General Jens Stoltenberg agreed Turkey's military operation against Kurdish forces in northeast Syria needed to end, a spokeswoman for Johnson's office said. 'The Prime Minister and Secretary General both expressed their deep concern at the situation in northern Syria,' the spokeswoman said in a statement after the pair met in London on Tuesday. 'Both leaders stressed the value of Turkey as a NATO ally and recognized the role they have played in supporting refugees from the Syrian conflict,' she added. 'But they were clear that the current Turkish operation needed to end.'