The U.S. Embassy in Stockholm, Sweden has issued a security advisory urging American citizens to exercise increased caution after an explosion occurred outside the U.S. Embassy in Oslo, Norway in the early hours of Sunday. The advisory was published on the embassy’s official website on March 8, following reports of the overnight incident. The embassy guidance is aimed at U.S. nationals residing in or travelling through Sweden. It asks Americans to maintain good personal security, avoid large gatherings, keep a low profile and exercise vigilance in public spaces, particularly near foreign diplomatic facilities. The advisory also refers to existing travel...