The PM maintains that while links of recent terror attacks have been traced back to Afghanistan, "but Pakistan is reopening border as a goodwill gesture".
Following a series of suicide bombings across Pakistan, the military blamed "hostile forces" in Afghanistan and ordered a shut down of the 1,510 mile porous and disputed border.
The premier was of the view that the prolonged closure of the Pak-Afghan border was against the interests of the people and the economies of the two countries. In this regard, he reiterated his resolve that Pakistan would continue its cooperation with Afghanistan for the elimination of terrorism.
The border closure, the worst since a two-week sealing in August, further undermines an already fragile relationship between the two countries, both of which accuse each other of harboring militant groups that carry out attacks.
"We have taken this decision on humanitarian grounds", a statement from Sharif's office said on Monday.
At face value, Pakistan's moves reflect concerns over Islamic militants crossing the border that has been disputed ever since Sir Mortimer Durand helped draw it up in 1893, when Britain ruled much of South Asia. The Prime Minister hoped that the Afghan Government would take measures to address the reasons for which the borders were closed. Tensions along the frontier have been simmering for months, after hundreds of thousands of Afghan refugees in Pakistan were repatriated past year, with Human Rights Watch accusing Islamabad of coercion, threats and abuse.
The closure left hundreds of thousands of people and lorries carrying food and other goods to Afghanistan stranded at the two major crossings of Torkham and Chammans. It also cut off Pakistani traders from a steady market. Torkham and Chaman were briefly opened on March 7-8 by Pakistan to allow Pakistani and Afghan citizens who had valid travel documents to return home.