The leader of the state Senate has surrendered to face charges including extortion and soliciting bribes amid a federal investigation into the awarding of a $12 million contract to a company that hired his son.

FBI officials said Republican Dean Skelos, of Long Island, surrendered at the bureau's office in Manhattan at about 9:30 a.m. Monday.

Skelos said last month he was cooperating fully and wouldn't resign his leadership post. He's hired an attorney in response to the investigation, which focuses on whether Skelos influenced Nassau County's decision to award the 2013 contract to Arizona-based AbTech.

Skelos' 32-year-old son Adam worked for the company as a consultant. Adam Skelos was charged also.

AbTech says it's cooperating with authorities and is not considered a target in the probe.