ISLAMABAD, Dec. 25 (Xinhua) -- Pakistan had freed 220 Indian fishermen as a goodwill gesture amid tension over cross-border fire exchanges in recent weeks, state radio reported on Sunday.

The fishermen, who had been detained for illegally entering Pakistani water for fishing, were freed from a jail in the port city of Karachi, Radio Pakistan reported.

They are expected to be handed over to the Indian authorities at the Wahga border on Monday.

Officials in Karachi said the freed Indians will be sent to the eastern city of Lahore by buses.

Pakistan and India routinely catch fishermen who cross water boundaries for illegal fishing.

Groups working for the welfare of such fishermen say the fishermen mistakenly enter other's waters as the two rivals have not yet reached an agreement on maritime boundaries.

The fishermen have been freed at a time when the relations between the two countries are tense following the attack on an army base in the Indian-controlled Kashmir in September that killed 19 soldiers.

India boycotted a regional summit in Islamabad in November that led to its postponement. However, Pakistan attended the Heart of Asia Ministerial Conference in the Indian city of Amritsar earlier this month.

Indian Prime Minister Naendra Modi on Sunday sent birthday greetings to his Pakistani counterpart Nawaz Sharif.

"Birthday wishes to Pakistan PM Mr. Nawaz Sharif. I pray for his long and healthy life," Prime Minister Modi said on his official Twitter.