Military intervention in Bahrain by Gulf states is unacceptable and it will only complicate the already volatile situation there, Iran's foreign ministry spokesman said on Tuesday.
"The presence of foreign forces cannot be acceptable and will make the situation more complicated and difficult," Ramin Mehmanparast said at his weekly press conference broadcast on state television.
Armed forces from Saudi Arabia and the United Arab Emirates rolled into Bahrain on Monday to help the Manama government deal with pro-democracy protesters.
Television footage showed convoys of unmarked, desert-brown armoured vehicles crossing from Saudi's Eastern Province into Bahrain, the home of the US Fifth Fleet.
"Basically, we do not think it is right for forces of other countries, specially Persian Gulf countries, to be present or intervene in Bahrain's situation," Mehmanparast said.
"The people of Bahrain have demands, which are legitimate and are being expressed peacefully. Any violence in response to these legitimate demands should be stopped," he added.
Bahrain's Shia-led opposition alliance has said any foreign force would be treated as an invading army.
"We consider the arrival of any soldier, or military vehicle, into Bahraini territory... an overt occupation of the kingdom of Bahrain and a conspiracy against the unarmed people of Bahrain," said an opposition statement.
But authorities called on the population to "cooperate fully and to welcome" the troops.
Mehmanparast said the solution to Bahrain "does not lie in interventions such as this, nor in the escalation of the crackdown and violent actions."
Iran's Foreign Minister Ali Akbar Salehi on Monday asked the Organisation of the Islamic Conference (OIC) to "use all means to prevent the use of violence" in Bahrain, the official IRNA news agency reported.
In a phone conversation with OIC Secretary-General Ekmeleddin Ihsanoglu, Salehi expressed his "concern at the aggravation of violence" in the kingdom, IRNA said.
Protests erupted in Shia-majority Bahrain on February 14 and seven people died in consequent crackdowns on demonstrations, according to an AFP tally based on relatives of victims and opposition officials.
Protesters on Monday blocked access roads to the Financial Harbour business complex in Manama, a day after more than 200 people were wounded there in clashes between riot police and demonstrators.
Bahrain, which has been ruled by a Sunni Muslim dynasty for more than 200 years, has transformed itself into a regional financial centre as it seeks to reduce dependence on diminishing oil revenues.
But many of the country's disenfranchised Shia see the banking district as a symbol of corruption, wealth and privilege, and opposition protesters are demanding far-reaching democratic reform.
The king has offered dialogue and a new, empowered parliament and other reforms but the opposition has refused to sit down to talks until the government resigns.
Predominantly Shia Iran has previously condemned Bahrain's use of "violence" against demonstrators, and repeatedly called on its authorities to address the "legitimate" demands of the population.
The Islamic republic, however, has refrained from calling for regime change, unlike what it advocated during uprisings in Egypt and Libya.
The United Nation's Ban Ki-moon noted his concern as he referred to reports of Saudi and Emirati troops entering Bahrain under the larger umbrella of the Gulf Cooperation Council as public protests continued in the small island kingdom.
A statement was issued Monday by the Secretary General's spokesperson saying that Ban was troubled that many people were injured in the protests explaining that the UN is in contact with both the Bahraini government and the opposition.
“The Secretary-General strongly believes that peaceful means should be adopted to ensure national unity and stability,” the statement said. “He appeals to all concerned to exercise maximum restraint and to do everything possible to prevent the use of force and further violence. He also underscores the responsibility of all parties to act in strict accordance with international human rights and humanitarian law.”
Ban urged for the end of violence in Bahrain last month andsaid he would be in touch with Middle East and North African leaderships calling for reform.