A gunman killed six people in the southern US state of Mississippi on Friday, prompting President Joe Biden to call again for tightened gun restrictions only days after he pleaded for action following a deadly university shooting.

Police in Mississippi said a man shot and killed a person at a store in the small town of Arkabutla, then went to a nearby house and killed a woman, according to local media.

CNN later reported, citing the county sheriff, that the woman was his ex-wife.

Police then tracked down his vehicle to a home later determined to belong to the suspect, and found two more men killed nearby, Sheriff Brad Lance told CNN.

The fifth and sixth person, a man and a woman, were found shot and killed in a neighboring house, and were possibly related to the suspect, who was detained as he attempted to flee, Lance said.

The Tate County Sheriff's Office identified the alleged shooter in a Facebook post as 52-year-old Richard Dale Crum, saying he was in custody and charged with first-degree murder.

In a tweeted statement, Mississippi Governor Tate Reeves said he had been briefed on the incident.

"At this time, we believe he acted alone. His motive is not known," said Reeves.

"Please pray for the victims of this tragic violence and their families at this time."

The case was taken on by the sheriff of Tate County, where Arkabutla is located, and the Mississippi Bureau of Investigation.

'Enough'

The deadly shooting Friday comes days after a man, also with no known motive, attacked a university campus in the northern state of Michigan, killing three people.

"Enough," said Biden in a statement released Friday night, echoing the same exasperated sentiment he expressed after the Michigan shooting.

"We are 48 days into the year and our nation has already suffered at least 73 mass shootings. Thoughts and prayers aren't enough. Gun violence is an epidemic and Congress must act now," Biden said.

Last month, two deadly mass shootings also occurred in less than a week, both in California and involving the Asian American community.

"We need -need- commonsense gun law reforms," Biden said Friday night.

His calls for Congress to reinstate a national ban on assault rifles, which existed from 1994 to 2004, has run up against opposition from Republicans, who are staunch defenders of the constitutional right to bear arms and have had a narrow majority in the House of Representatives since January.

There were an estimated 44,000 gun-related deaths in the United States last year, about half of them murder cases, accidents and self-defense, and half of them suicides, according to the Gun Violence Archive database.