New Delhi - Indian Prime Minister Manmohan Singh Tuesday said developing countries are affected worst by the global economic downturn and the upcoming Group of 20 (G20) meeting should address that by "coordinated and purposeful action."

"It is important and necessary for the summit to take credible decisions which will help to halt and reverse the current slowdown and to instill a sense of confidence in the global economy," Singh said in a statement before leaving for the G20 meeting in London starting Thursday.

Singh noted that the effects of the slowdown had spread across the world and developing countries, particularly those in Africa, were facing its worst consequences.

He said it was necessary to ensure adequate flow of finances to the developing countries to overcome the decline in international capital flows.

Issues that required focus were the need to avoid protectionism in the trade of both goods and services, facilitation of trade finance, and reform and restructuring of international financial institutions, he said.

"The time has come for the international economic and financial architecture to reflect contemporary economic strengths," Singh said.

Singh also said he looked forward to his first meeting with US President Barack Obama and to discuss regional and global issues of terrorism, the war in Afghanistan, energy security and climate change.

Earlier on Tuesday, Singh urged Pakistan to show "visible results" in its probe into the Mumbai terrorist attack if it wanted to resume the peace process with India.

"It (Pakistan) has to prove that the government is doing all that is possible (to bring the perpetrators to justice)," he said. "It is the least they should do to convince us of their sincerity," h,. e said.

The peace process stalled after the November 26 terrorist attacks carried out by the Pakistan-based Lashkar-e-Taiba terror group that left more than 170 people dead.

Singh's visit to London will be his first trip abroad after undergoing heart bypass surgery in January.

The G20 comprises Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, United Kingdom, United States and the European Union. (dpa)