(Reuters) - The gunman who killed two Virginia television journalists on air carried out a well-planned assault and identified with mass murderers and the Sept. 11, 2001, attacks on the United States, authorities said on Friday.

The shooter, Vester Flanagan, gave no sign of his destination or next move when he fled after gunning down the journalists from Roanoke station WDBJ7 on Wednesday, theFranklin County Sheriff's Office said in a statement.

"It is evident that Wednesday morning's attack was well-planned and premeditated" and Flanagan apparently acted alone, the statement on the shooting investigation said.

Flanagan, a former station employee, fired 17 rounds from a .40 caliber Glock pistol when he attacked reporter Alison Parker and cameraman Adam Ward as they were conducting a live interview at Smith Mountain Lake in southwest Virginia, the statement said.

Flanagan shot himself during a police chase in northern Virginia and died. The woman who was being interviewed was wounded and hospitalized.

Evidence and his writings show that Flanagan "closely identified with individuals who have committed domestic acts of violence and mass murder, as well as the Sept. 11, 2001, attacks on the U.S.," said the statement. Almost 3,000 people were killed in the 9/11 attacks.

The statement said two Glock pistols were recovered from Flanagan's rental car. No other firearms have been found.

The on-air killings have brought renewed calls for gun control in the United States and inVirginia, where the National Rifle Association gun lobby is headquartered.

Virginia Governor Terry McAuliffe, a Democrat, vowed to press ahead with legislation on background checks for gun buyers, although the Republican-led legislature has rejected his gun control efforts.

Citing a federal law enforcement source, USA Today said Flanagan had legally bought the handguns. He passed a background check despite his apparent emotional problems, it reported.

In a fax to ABC News the day of the shooting, Flanagan, who was black, called himself a "powder keg" over what he saw as racial discrimination. He was fired from CBS affiliate WDBJ7 in 2013.

A search warrant for Flanagan's rental car said police were tipped to him when he sent a text message to a friend "making reference to having done something stupid."

In the car, police found a pistol, 9mm ammunition, more magazines and a pistol case. Other items included stamped letters, a to-do list and briefcase with three license plates, a wig and sunglasses, the warrant said.

(Reporting by Ian Simpson in Washington; Additional reporting by Laila Kearney in New York; Editing by Susan Heavey and Eric Beech)