External Affairs Minister Pranab Mukherjee briefed top BJP leaders, including former Prime Minister Atal Bihari Vajpayee and Leader of the Opposition L K Advani, on Tuesday on the situation in immediate neighbourhood and on ties with Bangladesh, Pakistan, Afghanistan, Nepal, Bhutan and Sri Lanka, a statement issued by the Prime Minister's office said.

The luncheon meeting convened by the PM came days ahead of Mukherjee's trip to Pakistan to officially invite Pakistan President Pervez Musharraf for the Saarc summit to be held here in April.

Foreign Secretary Shivshanker Menon, National Security Adviser M K Narayanan, PM's special envoy to Pakistan S K Lambah, senior BJP leader and former Foreign Minister Jaswant Singh and former National Security Adviser Brajesh Mishra attended the meeting.

The purpose of the meeting was to keep the main opposition party in the loop on major initiatives of the government, especially on foreign policy, sources said.

The development came a little over a week after the PM drove down to Vapayee's residence on December 25 to greet the latter on his 82nd birthday, which was viewed by analysts as a bridge-building exercise.

The BJP had, of late, stepped up attacks on the government on a number of foreign policy issues, including dealing with terrorism, Pakistan and the Indo-US nuclear deal.

The BJP leaders were reportedly briefed on the status of negotiations on the Indo-US nuclear commerce deal after US Congress passed a historic legislation last month in the run up to the bilateral agreement to be discussed to implement the deal.

The BJP had, during the winter session of Parliament, accused the UPA government of converting into a "client state" of the US by accepting the terms of the deal. The main opposition had also flayed "unilateral" moves by the government on foreign policy front.