Nawaz Sharif was speaking at a joint press conference with President Ashraf Ghani after their talks in Islamabad.
The two sides reviewed the entire gamut of bilateral relations with focus on expanding cooperation in the areas of trade, investment, energy and building infrastructure, the leaders said.
"I reaffirmed Pakistan's support for the intra-Afghan reconciliation process that the new government is initiating. This process, we agreed, must be fully Afghan-led and Afghan-owned," the Pakistani prime minister said.
"I underlined Pakistan's commitment to comprehensively upgrade cooperation in all fields -- including border security and defense, Afghanistan's reconstruction and rehabilitation, capacity building, parliamentary exchanges, and cultural, educational and sports links," Nawaz Sharif said.
President Ghani, who arrived in Islamabad on his two-day state visit, called for the beginning of a new era of mutual trust and cooperation in all areas between the two countries, Xinhua reported.
"We are going to leave past behind and work for the future of Pakistan and Afghanistan. We are going to have renewed attentions, " President Ghani said.
Former Afghan president Hamid Karzai had complained that Pakistan had "not taken practical steps to encourage the Afghan Taliban come to the negotiation table." Pakistan argues it does not control the Taliban but is asking them to join the peace and reconciliation process.
"Time of words has passed. Now, let's work practically for security. We are going to work against terror through new framework," President Ghani said.
Expressing satisfaction at the outcome of his visit, the Afghan president said both countries "have overcome challenges of 30 years in three days today." He did not elaborate.
The Afghan president also invited Prime Minister Nawaz Sharif to visit his country.
Nawaz Sharif said both countries agreed that connectivity and regional economic cooperation are the indispensable elements of bilateral engagement.