* Incident occurs in eastern area hit by Shi'ite unrest
* Police storm house, circumstances of deaths disputed
DUBAI, Feb 20 (Reuters) - Two Saudi security officers and two people they were trying to detain were killed in a gunfight on Thursday in the eastern town of al-Awamiya, the government said, an area where minority Shi'ite Muslims have staged regular anti-government protests.
Shi'ites in the region complain of discrimination, a charge denied by Sunni Muslim-ruled Saudi Arabia, the world's largest oil exporter, and the Riyadh government blames Shi'ite-led neighbour Iran for the rise in tensions.
Saudi opposition activists said security forces stormed a home in Awamiya belonging to the brother of a man on a list of 23 people wanted by the authorities over unrest, before shooting dead two unarmed men they found inside.
They said one of the two was the house owner's 22-year-old son and the other a prominent local photographer known for documenting demonstrations and protester funerals that had taken place in the area over the past three years.
The wanted man was not in the house at the time, they said.
An Interior Ministry spokesman said security forces came under fire while trying to arrest "a number of armed troublemakers" who had previously fired on residents and security forces in Awamiya, according to state news agency SPA.
It said the security forces responded to the source of shooting in accordance with standing rules.
"As a result of the exchange of fire, the wanted men Ali Ahmed al-Faraj and Hussein Ali Madan al-Faraj were killed," SPA said, adding that two security men had also died and two more were wounded.
It said two pieces of weapons, a bullet-proof vest, a pair of binoculars used by snipers and a large amount of ammunition were found at the scene.
Local activists denied that there was any exchange of fire at the scene and said security forces burst into the house of a man in search of his wanted brother who was not there.
They said that Ali, the house owner's son, was shot 11 times while trying to run away. The second man, Hussein, died "as he documented the raid," one activist told Reuters.
A local news website, mirataljazeera.net, said Hussein, 34, had photographed many of the demonstrations and funerals of the more than 20 activists killed during unrest in Saudi Arabia's eastern region in the past three years.
The activists emailed several photos of the raid, one of which showed a body sprawled in the street with the upper torso naked, and another close-up image of a man who appeared to be dead lying on a blanket with his face stained with blood.
They also emailed pictures of blue armoured cars in various locations on the streets, which they said were near the scene of the incident. Reuters could not independently verify the authenticity of the photographs.
At least 21 people have been shot dead in the region since early 2011, when Shi'ites there staged protests against the involvement of Saudi forces in ending demonstrations in neighbouring Sunni-ruled Bahrain, which has a Shi'ite majority.
In 2012, Saudi Arabia ordered the arrest of 23 Shi'ites in Eastern Province, where many of the kingdom's minority Shi'ites live, saying they were responsible for unrest. Several have since either been killed or have been captured. (Reporting by Sami Aboudi; Editing by Mark Heinrich)