Dubai: Unidentified gunmen shot dead five people in Saudi Arabia`s Eastern Province late on Monday evening, the state news agency reported.
Nine people were wounded in the attack in al-Dalwah town in al-Ahsa district, a police spokesman was quoted as saying.
"As a group of citizens was leaving a building...three masked men opened fire at them with machine guns and pistols," the spokesman said, adding that the incident was under investigation.
It gave no further details. Al-Ahsa is one of the two main centres of minority Shi`ite Muslims in Sunni-ruled Saudi Arabia, along with the district of Qatif.
Videos purporting to show the aftermath of the attack posted to social media showed a body lying in a pool of blood outside a building, with people milling around calling for help. The authenticity of the videos could not immediately be confirmed.
One of the videos showed a man holding spent bullet casings at the bloodstained entrance to what appears to be a Shi`ite place of worship.
Shi`ite Muslims worldwide are holding ceremonies marking Ashoura, a 10-day event commemorating the death of the Prophet Mohammad`s grandson Imam Hussein in battle 1,300 years ago.
Qatif and Al-Ahsa have historically been the focal point of anti-government demonstrations in support of Shi`ites.
Shi`ites say they face discrimination in seeking educational opportunities or government employment and that they are referred to disparagingly in text books and by some Sunni officials and state-funded clerics.
They also complain of restrictions on setting up places of worship and marking Shi`ite holidays, and say that Qatif and al-Ahsa receive less state funding than Sunni communities of equivalent size.
The Saudi government denies allegations of discrimination.
A government census in 2001 said there were about a million Saudi Shi`ites. But U.S. diplomats in a 2008 embassy cable released by WikiLeaks estimated they represent up to 12 percent of the total Saudi population, which now numbers 20 million.