The Prime Minister has called upon all countries to act in concert in addressing the challenges the world is facing today. In his departure statement before leaving New Delhi for the United States to attend the 66th session of the United Nations General Assembly, Dr. Manmohan Singh said that global economy is in the midst of an economic slowdown with all its attendant problems, including inflationary pressures.He said, terrorism and non-traditional threats to international security, such as piracy, are threatening states and the international political and social order. Major upheavals in West Asia, North Africa and Gulf regions have made the future of this crucial part of the world uncertain.Dr. Singh said, it is time for the United Nations to resume its global leadership role. Underlining the need for early reforms of the UN, particuarly expansion of the Security Council, the Prime Minister said that the organisation must be seen as an impartial credible and effective body. He said, India's efforts at promoting international peace and security have enriched the Council's deliberations and enhanced its effectiveness.Dr. Singh will have bilateral meetings with the Presidents of Iran, South Sudan and Sri Lanka besides the Prime Ministers of Japan and Nepal. He will address the UN General Assembly on September 24. India's permanent representative to the UN, Hardeep Singh Puri said that Dr. Singh's address to the General Assembly is likely to focus on issues relating to removal of poverty, inclusive economic growth, environmental challenges and terrorism.Dr. Singh has left New Delhi a short while ago. Finance Minister, Pranab Mukherjee will also arrive in New York later today on a 5-day visit. The objective is to seek more investment in India by foreign investors and business leaders. He is scheduled to attend the meeting of G-20, G-24, BRICS and the IMF. Mr. Mukherjee will also participate in the meeting of the US-India CEO forum. ‘