BAGHDAD — A Hezbollah commander wanted by the United States has been released from Iraqi custody and returned to the Lebanese capital today, his lawyer said. The move is likely to complicate the Obama administration’s efforts to prosecute the militant believed to have been the mastermind of an attack that killed five U.S. soldiers.

The release of Lebanese-born Ali Mussa Daqduq also underscored how little influence Washington holds over Baghdad’s government since American troops left the country last December.

U.S. forces held Daqduq for four years, accusing him of masterminding a 2007 raid on an American military base in the Iraqi holy Shiite city of Karbala that killed five U.S. soldiers. He was handed over to Iraqi authorities when American troops left Iraq.

Two Iraqi courts, including the country’s central criminal court in July, subsequently found Daqduq not guilty of the Karbala attack. However, he was held under house arrest in the heavily fortified Green Zone in central Baghdad.

Daqduq’s lawyer, Abdul-Mahdi al-Mitairi, said Iraqi authorities decided to free the Hezbollah militant once U.S. elections were over. It appeared Iraqi officials did not want to embarrass President Barack Obama during his re-election campaign.