Iran has summoned the Pakistani ambassador to protest about a suicide bombing that killed 27 of its elite Revolutionary Guards near the border earlier this week, news agency Reuters reported citing local media on Sunday.
"If Pakistan does not carry out its responsibilities, Iran reserves the right to confront threats on its borders", Revolutionary Guards commander Major General Mohammad Ali Jafari was quoted by the state media.
The Wednesday bombing targeted a busload of Revolutionary Guards in the volatile southeastern province of Sistan-Baluchistan, which straddles the border with Pakistan.
The Sunni group Jaish al Adl (Army of Justice), which says it seeks greater rights and better living conditions for the ethnic minority Baluchis, claimed responsibility for the attack on Wednesday.
The attack was one of the deadliest on Iranian security forces in recent years and came just days after Iran held more than a week of celebrations for the 40th anniversary of the Islamic Revolution, which overthrew the US-backed shah.
Iran says militant groups operate from safe havens in Pakistan and have repeatedly called on the neighbouring country to crack down on them.
On Saturday, Iran's revolutionary chief Major General Mohammad Ali Jafari while addressing a large gathering warned Pakistan it would "pay a heavy price" for allegedly harbouring the terrorists in the country.
Meanwhile, India has also warned of strict action against Pakistan after 40 CRPF personnel were also killed in India's Jammu and Kashmir state.
A day after the attack in Iran, a terrorist rammed an explosive-laden vehicle to the army convoy. Dozens of personnel were also injured in the attack.
Both terror attacks have sparked international outrage against Pakistan and accused it of supporting the perpetrators.
Following the attack, India also summoned Pakistan's High Commissioner to the country.