Saudi Arabia vows to end violence with "iron fist"

* Riyadh blames Tehran for violence, protesters blame police

* At least six people killed since November - ministry

LONDON, Feb 20 (Reuters) - Saudi Arabia's Interior

Ministry said on Monday its security forces would use "an iron

fist" to end violence in a Shi'ite Muslim area of the country

and defended its tactics against what it called foreign-backed

troublemakers.

Sunni Muslim kingdom Saudi Arabia has blamed an unnamed

foreign power, widely understood to mean Shi'ite Iran, for

backing attacks on its security forces in its Eastern Province.

But members of the Shi'ite minority in the area have accused

the kingdom's own security force of using violence against

protesters.

"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 ministry said in a statement.

The statement came in response to a sermon preached in the

Qatif area of the Eastern Province last week that criticised the

government's handling of the situation, in which at least six

people have been killed, a ministry spokesman said.

Shi'ite activists in Qatif said the clashes first began at

the height of the Arab uprisings last year and were provoked by

the detention without charge of political campaigners.

Four people were killed in November, one in January and one

earlier this month, the interior ministry has said in past

statements.

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 which they

describe as heavy handed.

The government says it does not discriminate against

Shi'ites and has said the increased security is intended to

protect Qatif residents.

It has repeatedly blamed the clashes on people attacking

security forces.

The statement said the security forces were using "the

greatest restraint ... despite continuing provocations" and

"will not act except in self defence and will not initiate

confrontations".

"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 ministry's spokesman said in the statement.

Saudi Arabia and Iran have fought for influence across the

Middle East.

(Reporting By Angus McDowall; Editing by Andrew Heavens)