President Obama pledged late Monday to provide assistance "as needed" to stop the roving gangs who attacked Baltimore police and looted stores, setting at least one ablaze.

Obama was briefed on the situation by just sworn-in U.S. Attorney General Loretta Lynch and afterward pledged his administration’s commitment to provide assistance if necessary, according to the White House. The statement came about an hour after Maryland Gov. Larry Hogan activated the Maryland National Guard to help restore order.

Lynch assured Obama that the Justice Department “stands ready to provide any assistance that might be helpful there,” the White House added. The agency is already investigating possible civil rights violations by the Baltimore City Police Department in connection with the death of 25-year-old Freddie Gray. He was taken into police custody April 12, suffered an unexplained spinal injury and died April 19.

Obama also spoke with Baltimore Mayor Stephanie Rawlings-Blake and was scheduled to receive updates on the situation from White House Senior Adviser Valerie Jarrett and Lynch.

In a statement released Monday night, Lynch said, “I condemn the senseless acts of violence by some individuals in Baltimore that have resulted in harm to law enforcement officers, destruction of property and a shattering of the peace in the city of Baltimore...The Department of Justice stands ready to provide any assistance that might be helpful."

“Today’s looting and acts of violence in Baltimore will not be tolerated,” Hogan said before declaring a state of emergency and calling up the Guard. “I strongly condemn the actions of the offenders who are engaged in direct attacks against innocent civilians, businesses and law enforcement officers. There is a significant difference between protesting and violence and those committing these acts will be prosecuted under the fullest extent of the law.”

Hogan signed the order at the request of the city.

An aide to former Maryland Gov. Martin O'Malley confirmed to Fox he had canceled several paid speeches in Ireland in order to return to his home state amid the riots and looting.

O'Malley is now planning to be in Baltimore Tuesday morning. He previously served as the city's mayor before becoming governor.

O'Malley, who is mulling a bid for the Democratic presidential nomination, posted two messages on Twitter on Monday night urging calm and healing.

"This is terrible," Maryland Democratic Sen. Barbara Mikulski told reporters in the U.S. Capitol Monday night.

Sen. Ben Cardin, D-Md., said the "immediate concern is to restore the peace in Baltimore."

The Associated Press contributed to this report.