Details added (the first news was posted at 20:55)
Iranian Foreign Ministry on Tuesday summoned the ambassador of Switzerland, representing U.S. interests, in connection with U.S. support for the introduction of foreign troops in Bahrain, İRİB news agency reported.
Diplomatic relations between the U.S. and Iran broke after the 1979 Islamic revolution. The U.S. interests in Iran are represented by Switzerland.
Earlier the ambassador of Saudi Arabia and Charge d'affaires of Bahrain were also summoned to the Foreign Ministry of Iran regarding the military sent to Bahrain, the official website of the Iranian Foreign Ministry reported.
Deployment of troops of Saudi Arabia in Bahrain has aggravated the situation in the country, the head of the Ministry's department for the Persian Gulf and the Middle East Hoseynamir Abdolahian said at a meeting with the ambassador.
On Monday, more than 1,000 military personnel from Saudi Arabia, sent by the Cooperation Council for the Arab States of the Gulf (GCC), arrived in Bahrain to take part in a mission of maintaining order and security.
In mid-February, the foreign ministries of oil-producing monarchies of the Persian Gulf expressed the full support to the authorities of Bahrain and opposed any outside interference in the affairs of the Kingdom.
Early last week, the GCC discussed the possibility of establishing a joint fund for financial assistance to Bahrain and Oman, which are covered by demonstrations of an economic nature.
Unauthorized demonstrations in Bahrain began in mid-February. The first protest took place in a Shiite village Karkazan located in the south metropolitan region of Manama, and then spread to other cities. The protesters demanded the reform of the government.
Thousands of demonstrators spent several days in a temporary tent camp on the Pearl square in Manama, urging people in the country to organize a demonstration with the requirements to the authorities to carry out political reforms. The police brutally suppressed any actions in the country.
In recent months, many countries in the Middle East and North Africa have been covered by massive popular protests, which have already led to the downfall of the ruling regimes in Egypt and Tunisia. At the present time unrests continue particularly in Yemen, Oman and Bahrain.
Anti-government demonstrations were also held earlier in Algeria, Iraq, Jordan and Morocco. The most violent clashes have been taking place since February 15 in Libya, where, according to international organizations, several thousands of people have already been killed.
The GCC consists of six countries: Bahrain, Kuwait, Qatar, UAE, Oman and Saudi Arabia. These countries conduct multilateral economic integration, the core of which consists of four countries: Saudi Arabia, Bahrain, Qatar and Kuwait.