Iran has delivered an official note of protest to Pakistan's chargé d'affaires in Tehran over a deadly attack on Iranian border guards through the Pakistani territory, PressTV reported.
The protest note was submitted to Sohail Siddiqui by a senior Iranian Foreign Ministry official in a meeting on Saturday.
Fourteen Iranian border guards were killed on Friday night and six were wounded in a terrorist attack in the border city of Saravan in the country's southeastern province of Sistan-Baluchestan. Three border guards were also taken hostage by the assailants.
In the meeting, the Iranian side strongly demanded that Islamabad act in accordance with the security pact and extradition treaty signed between the two countries, and apprehend the ringleaders as well as members of the terrorist grouping who fled to Pakistan after the deadly incident.
In February, Iran and Pakistan signed a security agreement under which both countries are required to cooperate in preventing and combating organized crime, fighting terrorism and countering activities which pose a threat to the national security of either country.
The Pakistani diplomat expressed sorrow over the deaths of the Iranian border guards in the shoot-out, saying he would convey Tehran's protest to his respective government.
Earlier on Saturday, Iran's Deputy Interior Minister for Security Affairs Ali Abdollahi called on Islamabad to step up its border security to curb terrorist activities.
Abdollahi said no group has yet claimed responsibility for the attack, and that serious measures were underway to secure the release of the abducted guards.
The incident prompted the Iranian Interior and Foreign Ministries to launch a joint investigation while the Supreme National Security Council is to convene on Sunday to look into the incident.