Saudi Arabia has accused another country of inciting Monday's second wave of rioting in the oil-rich Eastern Province that injured 14 people, including 11 security personnel.

"A foreign country is trying to undermine national security by inciting strife in Qatif," Saudi state television cited the interior ministry as saying on Tuesday, according to Al Jazeera.

The statement was a veiled reference to regional rival Iran as the rioters were Shiite Muslims, who constitute most of the population of the neighboring country.

An official from the ministry said men in motorbikes and carrying Molotov cocktails gathered at a roundabout in Awamiya and clashed with policemen who tried to disperse them. Petrol bombs were hurled and nine policemen were shot, according to the ministry.

US-based Saudi activist Ali Al Ahmed claimed in an email that the protesters surrounded a police station to demand the release of two detained activists before the rioting erupted.

Shiites, who constitute about 2 million of the Eastern Province's population, have been demanding equal treatment from the Sunni dominated Saudi Arabia. In March, Shiites in Qatif held protest rallies, which are banned in the country. The protest was quickly quelled.