WASHINGTON, July 23 (Reuters) - The U.S. military said it carried out an airstrike on Friday against al Shabaab militants in Somalia, in the second such action this week. The Pentagon said the strike took place in the vicinity of Galmudug, Somalia, and emphasized that no U.S. forces were accompanying Somali troops during the operation. It came just three days after a similar U.S. strike targeting the al Qaeda-linked Islamist group, which is seeking to topple the Somali government and impose its strict interpretation of Islamic sharia law. "U.S. forces are authorized to conduct strikes in support of combatant commander designated partner forces under collective self-defense," the Pentagon statement said. Al Shabaab has targeted Somali military bases and civilian infrastructure including hotels, bars and schools in both Somalia and neighboring countries. The strikes came as some of President Joe Biden"s fellow Democrats try to rein in war powers authorizing such military actions overseas. On Thursday, several lawmakers, including Democratic Senator Chris Murphy, who leads a key Senate foreign relations subcommittee, criticized the Pentagon for carrying out the strikes even when no U.S. forces were in danger. "It"s time to do away with questionable legal justifications claimed by one administration after the next for acts of war like this," Murphy said in a statement.