ISLAMABAD/TEHRAN - Tehran on Wednesday issued a warning to Islamabad after reports emerged that an Iranian soldier abducted and taken across the border into Pakistan by extremists had been executed.

President Hassan Rouhani in a telephone call with Pakistan’s Prime Minister Nawaz Sharif demanded “serious and swift action” by Pakistan to secure the release of the soldiers.

“We expect to hear good news in this regard,” he said, while calling for “joint action by both countries against terrorists,” the official IRNA news agency reported.

For his part, Nawaz Sharif said the issue was of “utmost importance” to his government and that he was “prepared to boost action to free the soldiers”.

Iran’s Foreign Minister Mohammad Javad Zarif expressed “grave concern” about the fate of Jamshid Danayifar, who was kidnapped along with four other border guards on February 6 by rebel group Jaish-ul Adl. “We did all we could to secure their release,” Zarif told state television after a cabinet meeting. But it is disappointing that Pakistan has failed to secure its borders, and allows terrorists to operate on its soil.”

Zarif’s remarks came after his ministry summoned Pakistani ambassador Nour Mohammad Jadmani, demanding “swift and serious action” to secure the release of the soldiers, the official IRNA news agency reported.

An Iranian official said the Pakistani ambassador was summoned as part of Iran’s serious follow-up on the whereabouts of kidnapped Iranian border guards and to remind the Pakistani government of the need to take urgent action for the identification and capture of those behind the killing of an Iranian border guard and their extradition to Iran. Interior Minister Abdolreza Rahmani-Fazli meanwhile warned - without elaborating - that Iran “reserves the right to utilise all its ability in its border areas.”

Jaish-ul Adl said on its website on Sunday that Danayifar had been killed, warning of further executions should Tehran refuse to ‘release Sunni prisoners’. Iran’s interior ministry says it is awaiting Islamabad’s official position amid media reports that local Pakistani authorities have confirmed the group’s claim.

Pakistan said Wednesday it is deeply saddened over the reported killing of one of the five Iranian border guards, abducted in the Sistan-Balochistan province of Iran last month. “We condemn this terrorist act, and share the grief and agony of the families of the martyr and the other border guards,” Foreign Office spokesperson said in a statement in Islamabad.

The spokesperson said that in the wake of the border incident, the Government of Pakistan has extended all possible support in tracking whereabouts of the missing Iranian border guards.

The statement said that during the last meeting of the Joint Border Commission in Quetta on February 19-20, 2014, a Border Coordination Committee was also established to assist with the effort.

“The Government of Pakistan stands ready to act on any credible and actionable intelligence made available to it. However, our investigations have neither corroborated nor established the entry into or presence within Pakistani territory of the Iranian border guards”, it added.

It further said that Pakistan deeply values its brotherly relations with Iran and the two countries are engaged in a number of bilateral processes to forge a closer and cooperative relationship for the common benefit of the people of our two countries.