Iranian Foreign Minister Kamal Kharrazi on Saturday termed the shooting at the Britain embassy in Tehran as "irrational."
"We are investigating the case because embassies should enjoy full security," Kharrazi said.
The British embassy in Tehran closed on Wednesday after five shots were fired at its premises from a nearby street, the incident left no casualties and the embassy would remain closed until further notice, an embassy official said.
Iranian police have launched extensive investigation right after the shooting incident took place, but no outcome has been announced yet.
The incident followed a fierce diplomatic spate between Tehran and London over the arrest of former Iranian ambassador to Argentina, Hadi Soleimanpour, by the British police in late August.
Soleimanpour was arrested in Durham, northeastern England, for his alleged involvement in a 1994 bombing of a Jewish community center in Buenos Aires that left 85 killed and 200 injured.
An Argentine judge issued arrest warrants for Soleimanpour and seven other Iranian diplomats for their alleged involvement in the 1994 bombing.
Iran has repeatedly denied the charges, stressing that Argentinais playing politics over the issue under the Zionist pressure.
Calling the warrants "null and void", Iran broke off economic and cultural cooperation with Argentina.
Observers believed the shooting incident at the British embassy probably has some connection with the arrest of Soleimanpour by theBritish police.
The Iranian government has so far failed in its efforts to secure the release of the former envoy held by Britain.