British and Iranian sources said five bullets were fired at the Embassy’s huge building situated in central Tehran, breaking windows, but injuring no one.

The Embassy was closed until further notice, as the British ambassador in Iran, Mr. Richard Dalton, got in contact with the Iranian Foreign Affairs Minister Kamal Kharrazi.

Hamid Reza Asefi, the senior spokesman for the Foreign Affairs Ministry, condemned the incident and said that Police have launched extensive investigations into the case, the official Iranian news agency IRNA reported on the incident.

"The (British) Embassy is guarded jointly by the Police and Foreign Affairs Ministry and everything is under control", Asefi assured.

No one or group has claimed the gunfire, but IRNA quoted some witnesses as having said that two motorcyclists fired into the Embassy.

Green Stock, the Embassy’s press attache told IRNA that five bullets fired toward the embassy building at 11:40 on Wednesday, broke the windows and entered the building.

The Foreign Office said that it was "much too early" to say who was responsible for the shooting.

However, A Foreign Office spokesman said that the acting head of the Iranian Embassy in London, Majid Qahremani, was summoned Wednesday to discuss the incident.

Scotland Yard arrested Mr. Soleymanpour on an international warrant issued early in August by Argentinean judge Juan Jose Galeano, seeking the former ambassador for his alleged participation in the bombing of the Jewish centre in Buenos Aires on July 1994, killing 85 and wounding 300.

Iran protested to both London and Buenos Aires over the arrest of Mr. Soleymanpour and retaliated against Argentine by cutting all trade and cultural ties.

In telephone conversation with his Iranian counterpart, British Foreign Secretary Jack Straw explained to him that the arrest of Mr. Soleymanpour is a judicial matter, having nothing to do with the government.

A Court in London decided to keep Mr. Soleymanpour in custody despite warnings from Tehran that keeping the former diplomat in prison might harm Iran-London’s newly improved relations.

Iran also had warned London that in case Mr. Soleymanpour is handed over to Argentine, it would certainly affect negatively relations between the two sides, a warning that stops short of meaning Mr. Dalton would be expelled from Tehran.

Hard-line Iranian newspapers like the evening daily "Keyhan", a mouthpiece of the Iran’s leader Ayatollah Ali Khameneh’i have called for Mr Dalton to be expelled in protest.

The British government Wednesday welcomed Iran’s immediate response to a shooting incident at its embassy in Tehran.

"We welcomed assurances about conducting an investigation and immediately increasing security around the Embassy", the spokesman said, quoted by IRNA.

According to IRNA, Mr. Sarmadi had been recalled back in Tehran after failing to secure the release of Mr. Soleymanpour.

German intelligence and counter espionage agents as well as two Iranians witnesses who were in contacts with Mr. Sadri gave evidences on his activities on behalf of Iranian intelligence services. Mr. Sadri is accused of having infiltrated monarchist organisations by posing as an opponent to the ayatollahs regime and report back to Tehran about their activities in Germany and other European countries.

Mr. Morteza Ra’isi, a correspondent for the Persian service of the BBC said Tehran got interested in monarchist groups after they had become more active and in case it is proved that the accused was effectively working for the Iranians, then Tehran’s relations with Berlin, Iran’s main political backer and trading partner, might suffer.

The Vienna-based International Atomic Energy Agency has also expressed concern over the "opacity" of the Islamic Republic’s nuclear programs and gave Iran until 8 September to accept the protocols or the case would be passed to the United Nations Security Council for decision, which might result in international sanctions.