Islamabad: Pakistan on Thursday said it was yet to decide on attending a NATO Summit next month that will focus on Afghanistan though it was developing a "work plan" on resetting ties with the US on the basis of guidelines approved by its Parliament.

Foreign Office spokesman Moazzam Khan said "no final decision" had been made on Pakistan's participation in the NATO Summit to be held in Chicago during May 20-21 or on a visit to Islamabad by US Special Representative for Afghanistan and Pakistan Marc Grossman.

At the same time, the government is developing a "work plan" for new terms of engagement with the US in line with guidelines that were recently approved by a joint session of parliament, Khan told a weekly news briefing.

The NATO Summit in Chicago is expected to discuss key issues like funding of Afghan security expenditure and foreign troop levels in the war-torn country in the period up to 2014.

In recent weeks, the US has been in contact with the Pakistan government to ensure its participation in the NATO Summit.

Prime Minister Yousuf Raza Gilani ordered a parliamentary review of ties with the US after a cross-border NATO air strike killed 24 Pakistani soldiers in November.

The attack has held up cooperation between Pakistan and the US on finalising the endgame in Afghanistan ahead of the withdrawal of American and other foreign forces.

Following the approval of guidelines by parliament, Pakistan's top civil and military leadership decided to negotiate new terms for joint counter-terrorism cooperation and the reopening of NATO supply routes which were closed.