According to the Pakistan Foreign Office, Imran is said to have expressed gratitude over 'Iran's support' on the issue.
The government, however, warned of the likelihood of large-scale militant attacks.
Nearly 100 security personnel have been injured in stone pelting protests in last two months.
Yawar Mir, Noor Mohammed and Shoiab Lone were be released on various grounds, the officials said, explaining the reasons for ending of their detention.
Restrictions were imposed when New Delhi on August 5 scrapped the special status of Jammu and Kashmir state under Article 370 of the Constitution and bifurcated it into two Union Territories.
A document reveals a meeting was held at a location in Pulwama last week where three terror groups were briefed about the responsibilities assigned to them by their masters.
Official sources said majority of the newly-approved projects in the Valley are pending for want of bidders, as the e-tendering of projects has been severely affected.
Panda said that the most shocking thing is that Pakistan having invaded Kashmir and illegally occupied a portion and a part of that portion has been given to China.
While Jammu-based leaders have been released, a similar move in Kashmir is unlikely soon.
The terrorists hurled a grenade on a security patrol outside the heavily guarded complex in Anantnag town, 55 km from here, around 11 am, an official said.
A senior administration official said that these leaders were never detained and were free to participate in political activities.
A senior official of the state government said the quantum and frequency of these relaxations has been progressively increasing to a point that now almost the entire state is free of restrictions.
Mobile services remained suspended in Kashmir except in Handwara and Kupwara areas in the north, while Internet services -- across all platforms, continued to be snapped in the valley.
The Home Minister said that the region will be the most developed area in the country in the next 5-7 years because of the abrogation of Article 370.
Restrictions were imposed when New Delhi had on August 5 scrapped the state's special status under Article 370 of the Constitution and bifurcated in into Union Territories.