WASHINGTON, June 18 -- U.S. President Barack Obama on Thursday expressed anger over a black church massacre in the southeastern U.S. city of Charleston and said the country has to face the fact that rampant gun violence only happens in the United States.

"I don't need to be constraint about the emotions that tragedies like this raise," said Obama in his first speech after the shooting spree at the Emanuel African Methodist Episcopal Church in Charleston, South Carolina. "To say our thoughts and prayers are with them and their families ... doesn't say enough to convey the heartache and the sadness and the anger that we feel."

Calling Wednesday night's hate crime shooting that killed nine black people "senseless", Obama said the country has to shift how it thinks about the issue of gun violence collectively.

With a complexion of both sobriety and frustration, Obama said that six and half years into his presidency, he had had to make statements like the one he made on Charleston black church shooting too many times.

"Once again, innocent people were killed in part because someone who wanted to inflict harm had no trouble getting a gun," he said. "This type of mass violence does not happen in other advanced countries. It doesn't happen in other places with this kind of frequency."

Earlier on Thursday, Dylann Roof, a 21-year-old white man identified by the police as the suspect, was caught about 14 hours after the shooting in Shelby, North Carolina during a traffic stop, said Charleston police chief Gregory Mullen.

"We have a lot more investigation to do to find out why this happened," said Mullen. ""We don't know if anybody was targeted other than the church itself."

Earlier Thursday, U.S. Attorney General Loretta Lynch announced that the U.S. Justice Department had already opened a hate crime investigation into this shooting at the historic black church.

According to the police, Roof stayed at a prayer meeting for almost one hour Wednesday night before opening fire. A law enforcement official was quoted by the U.S. TV network CNN as saying that witnesses told them that the suspect said he was at the church "to shoot black people."

Nine people, all black, were killed in the shooting spree and three people survived, including a female. She was quoted by local media as saying that the shooter told her he let her live to tell everyone else what happened.

"The only reason someone could walk into church and shoot people praying is out of hate," said Charleston Mayor Joe Riley during a press conference on Wednesday night.

Built in 1891, the church is one of the most prominent black churches in the country and has one of the largest black congregations in the region, said the website of the church.