A roadside bomb exploded in northwest Pakistan on Sunday, hitting a convoy of foreign diplomats. The diplomats were traveling through the region with police protection when the blast occurred, killing one officer and injuring three others.

According to Zahidullah Khan, a police officer from the Swat district, the diplomats were on their way to a popular tourist resort in the Swat Valley. They were being escorted by a police van when an improvised explosive device (IED) suddenly went off,...