RIYADH (Reuters) - Three Saudi security officers were wounded, one critically, by gunfire outside a police station in a flashpoint village in the mostly Shi'ite Muslim area of Qatif, the government said on Tuesday.

The incident, which an Interior Ministry spokesman said had taken place on Monday night, follows four deaths during a police raid in the same village, al-Awamiyah, last week, as tensions with minority Shi'ites rise after months of comparative calm.

"While a number of security men were in front of the Awamiyah police headquarters discharging their duties, they were exposed to heavy fire by unknown people from a neighbouring farm which wounded three of them, one critically," the official Saudi Press Agency reported, citing an Interior Ministry spokesman.

It said the authorities were working to identify those responsible.

In last week's incident, police raided a house looking for a man wanted in connection with unrest, and an exchange of fire led to the deaths of two of the house's inhabitants and two members of the security forces.

Shi'ites in Saudi Arabia, where the ruling family and most people follow the strict Wahhabi school of Sunni Islam, often complain of entrenched discrimination, a charge the authorities deny.

Protests erupted in the Qatif district of Eastern Province during the Arab uprisings in 2011 and sputtered on into mid-2012, leading to 17 deaths. There have been renewed outbreaks of violence several times since.

Shi'ites say it is harder for them to build and run places of worship than for Sunnis, that they are denied senior positions in local government or public sector employment, and that Shi'ite-majority districts get less state investment.

Human rights activists in Qatif have also accused the government of arbitrary arrests, torture and shooting unarmed protesters.

The government denies all these charges and has said the unrest in Qatif was stirred by Iran, Riyadh's main regional rival and the biggest Shi'ite power. The protesters and the government in Tehran deny this.

(Reporting By Angus McDowall; Editing by Alistair Lyon)