Washington:  A white gunman was at large early on Thursday after he shot and killed several people at a historic black church in downtown Charleston, South Carolina in a gruesome attack police called a hate crime.

Worshippers were attending a prayer meeting in the Emanuel African Methodist Episcopal Church on Wednesday evening when the gunman walked in and opened fire, Charleston Police Chief Gregory Mullen said.

The shooting comes at a time of heightened racial tensions in America, after several high-profile killings of unarmed black men at the hands of white police in recent months led to riots and a national debate on race.

In Wednesday’s shooting, eight people were killed inside the church, and another victim died at a trauma center shortly after. Several other people were wounded.

‘At this point, we have nine victims in this hideous crime that has been committed,’ Mullen told journalists.

Police said the suspect was a clean-shaven white man in his early 20s.

As of 2:00am on Thursday (0600 GMT), he remained at large and officers swarmed across the city to try to find him.

The shooting’s designation as a hate crime means federal authorities will help with the investigation and could assist in an eventual prosecution.

Officers also investigated a possible bomb threat after the shooting, but several hours later gave the all-clear.

The Holy City

Charleston is known locally as ‘The Holy City,’ due to its large number of churches and historical mix of immigrant ethnic groups that brought a variety of creeds to the city on the Atlantic coast.

‘This is the most unspeakable and heart-breaking tragedy,’ Mayor Joseph Riley said.

‘People (were) in prayer on a Wednesday evening. A ritual coming together, praying and worshipping God. To have an awful person come in and shoot them is, is inexplicable.’

Officials did not immediately release the names or any details of the victims.

According to its website, the Emanuel African Methodist Episcopal Church it is the oldest such church in America’s southern states.

‘The only reason someone can walk in to church and shoot people praying is out of hate,’ Riley said. ‘It is the most dastardly act that one can possibly imagine.’

‘We’ll never understand what motivates anyone to enter one of our places of worship and take the life of another,’ South Carolina Governor Nikki Haley said in a statement.

Because of the shooting, Republican presidential candidate Jeb Bush canceled campaign events that had been planned for Thursday in Charleston.

‘Governor Bush’s thoughts and prayers are with the individuals and families affected by this tragedy,’ his campaign said in a statement.

Democratic presidential candidate Hillary Clinton also tweeted her condolences.

‘Heartbreaking news from Charleston - my thoughts and prayers are with you all,’ she wrote.

The incident once again brings to the fore the racial tensions that persist in many communities in America, more than five decades after the Civil Rights Act was enacted to outlaw racial and other forms of discrimination.

High-profile police killings of unarmed black men have prompted riots, as well as much soul-searching and national debate in recent months as America grapples with its troubled racial past.

Charleston is a popular tourist destination known for its cobblestone streets, Southern cuisine and nearby beaches and islands. The city is also known outside the United States for its namesake 1920s dance.