U.S. support for the Lebanese Armed Forces is moving forward with new urgency, as Beirut battles to push back Islamic extremist groups that have launched unrelenting attacks along the frontier with Syria.

On Wednesday, the Lebanese army conducted live-fire demonstrations using advanced missiles supplied by the United States in the troubled Baalbek region in the east, where army troops have endured repeated attacks by Islamic extremist groups, including Islamic State and the al-Qaida-linked Nusra Front.

The military exercises followed a U.S. State Department announcement that it had approved the possible sale to Lebanon of six A-29 Super Tucano aircraft and associated equipment, parts and logistical support, worth an estimated $462 million. […]