Updated

An American-born clerk at a home improvement store on New York's Long Island has been charged by federal prosecutors with conspiracy to commit murder abroad, obstruction of justice and attempting to support terrorists.

Twenty-five-year-old Marcos Alonso Zea has pleaded not guilty. He was arraigned and detained without bail following his Friday arrest. His lawyer did not comment after his court appearance.

Authorities say Zea planned to travel overseas to wage violent jihad. They say in January he attempted to fly to Yemen by way of London to join Ansar al-Sharia, a group authorities say is an alias for al-Qaida in the Arabian Peninsula. But customs officials in London rejected him and returned him to the U.S.

A co-conspirator has pleaded guilty to charges including attempting to provide support to terrorists.