WASHINGTON House Majority Whip Steve Scalise (R-La.) was still in critical condition on Thursday after a lone gunman opened fire Wednesday morning on a group of Republican lawmakers practicing for a congressional baseball game.

Six people, including two congressmen, two police officers, a congressional aide and a lobbyist, were injured in the attack in an Alexandria, Virginia, park. The assailant, who authorities have identified as 66-year-old James T. Hodgkinson of Belleville, Illinois, was shot by police and later died of his injuries at a hospital.

Scalise underwent surgery at the MedStar Washington Hospital Center after being shot in the hip. In a statement Wednesday night, the hospital said Scalise sustained a single rifle shot to the left hip that travelled across his pelvis, fracturing bones, injuring internal organs and causing severe bleeding.

He underwent immediate surgery and an additional procedure to stop bleeding, the hospital said, noting the congressman had received multiple blood transfusions and remained in critical condition late Wednesday. It said Scalise would need further operations.

Before the surgery, Scalise was in good spirits and spoke to his wife by phone, his office said. President Donald Trump and first lady Melania Trump on Wednesday night visited Scalise in the hospital , bringing flowers and offering support to the lawmakers family.

The Trumps also met with Crystal Griner, one of the two U.S. Capitol Police officers injured in the attack, and her wife. Griner and David Bailey, the other officer hurt, are in stable condition, according to Chief Matthew R. Verderosa.

Vice President Mike Pence and second lady Karen Pence also checked in on Scalise and Griner on Thursday .

Zachary Barth, a staffer for Rep. Roger Williams (R-Texas), was shot in the leg . He was transported to a local hospital and has since been released. Williams sustained a minor leg injury.

Matt Mika, director of government relations for Tyson Foods Washington, D.C., office, was also among those shot. His condition was upgraded from critical to serious on Thursday, a spokeswoman for George Washington University Hospital confirmed to HuffPost.

The attack took place shortly after 7 a.m. at Eugene Simpson Stadium Park, less than 8 miles south of the White House. U.S. Capitol Police officers assigned to Scalise engaged Hodgkinson in gunfire, and Alexandria Police responded soon after. At that point, we were able to calm the situation, and victims were transported to the hospital, Verderosa said.

The FBI is investigating Hodgkinson and his possible motives. Its too early to determine whether the attack was politically motivated, authorities said.

The shooters weapons a 9 mm handgun and 7.62-caliber rifle were recovered at the scene by law enforcement officials. The Bureau of Alcohol, Tobacco, Firearms and Explosives ran traces on the weapons and found no evidence to suggest Hodgkinson purchased the firearms illegally, according to an FBI statement released Thursday.

The FBI said it was processing a cell phone, a computer and a camera recovered from Hodgkinsons van, which was in the parking lot of a YMCA adjacent to the park.

Sen. Bernie Sanders (I-Vt.) confirmed on Wednesday that Hodgkinson had volunteered for his presidential campaign. Let me be as clear as I can be, Sanders said in a statement. Violence of any kind is unacceptable in our society and I condemn this action in the strongest possible terms.