At least 13 people, including four children, were killed in a counterterrorism operation mounted early Thursday by US special forces in an area in Syria where militants are active, a war monitor reported. The Syrian Observatory for Human Rights added that a US-led military coalition carried out airstrikes and conducted a land-borne operation during which a firefight took place in north-western Syria. The British-based watchdog did not specify who was targeted in the raid, but activists in the area said it might be an Islamic State or al-Qaeda hideout. The operation took place in the Syrian are…