Islamist al Shabaab militants killed at least seven soldiers at a Somali military base in a town re-captured by the government, the information ministry and militant group said. The attack was eventually repelled, an officer at the base in the central Somali town of Galcad told Reuters. He said the dead included the base's deputy commander, who was part of a U.S.-trained unit stationed there. The attack underscores the formidable threat al Shabaab poses for Somalia's military, even after a government offensive launched last year scored significant success against the al Qaeda-allied militants. Al Shabaab fighters stormed the Galcad base…