Saudi Arabia has vowed to use an \"iron fist\" to halt attacks against security forces in the country\'s east. The Sunni Muslim kingdom has accused an unnamed foreign power, widely understood to mean Shiite Iran, of backing attacks on its forces in the Eastern Province. Shiite activists have accused the kingdom\'s own security force of using violence against protesters. Clashes first began at the height of the Arab uprisings last year and were provoked by the detention without charge of political campaigners \"It is the state\'s right to confront those that confront it first... and the Saudi Arabian security forces will confront such situations... with determination and force and with an iron first,\" the interior ministry said in a statement. \"Some of those few (who attacked security forces) are manipulated by foreign hands because of the kingdom\'s honourable foreign policy positions towards Arab and Islamic countries.\" The statement came in response to a sermon preached in the Qatif area of the Eastern Province last week which criticised the government\'s handling of the situation, in which at least six people were killed. Members of the minority have long complained of discrimination, which they say makes it harder for them to find government jobs, attend university or worship in open, than members of the Sunni majority. Since the protests and clashes started last year, they have also complained of police checkpoints and patrols. However, the government denies discriminating against Shiites and said the increased security is intended to protect Qatif residents and repeatedly blamed the violence on attacks on security forces. Four people were killed in November, one in January and one earlier this month, the interior ministry has said in past statements.