The presidents of Pakistan, Afghanistan and Russia agreed on Wednesday to pursue joint economic projects to help bring stability to the volatile region as they met for a rare regional summit. The four-way summit, which also involved Tajikistan, adopted a joint declaration, saying it supported intentions by businesspeople from Russia, Pakistan and Tajikistan to help Afghanistan rebuild its infrastructure, including in energy and transportation industries. Priority should be given to works on the Salang tunnel linking northern and southern parts of Afghanistan, oil and gas projects in the north of the country, a fertilizer factory and an electric power station in Mazar-i-Sharif and a home-building factory in Kabul, among others, the statement said. Russian President Dmitry Medvedev hosted Afghan counterpart Hamid Karzai, Pakistan leader Asif Ali Zardari and Emomaly Rahmon of Tajikistan in the Black Sea resort of Sochi. The leaders also called for pursuing joint regional projects, including a project codenamed CASA-1000, whose aim will be sending power from Tajikistan to Afghanistan and Pakistan. Russian Foreign Minister Sergei Lavrov told reporters that the project “unfortunately exists only on paper” and that the three countries had invited Russia to participate in it. “Our interest in it exists,” Lavrov said. “The significance of this project for the stabilization of the regional situation ... is hard to overestimate.” Speaking earlier at the summit, Medvedev said the four countries should revive economic cooperation that dated back to the Soviet era. “I think it makes sense to return to them to try to give additional impetus to the economic development (and) solve a whole number of urgent tasks, including in energy and social development,” Medvedev said. The four leaders agreed that “economics is the key to overcoming all problems,” Lavrov said. Meanwhile, regular flights between Russia and Georgia are to be restored, two years after the two nations fought a brief war, the private Russian airline S7 said on Wednesday. Rossaviatsia, Russia's federal agency for air transport, gave the green light to S7 to resume flights between Russia and Georgia, but did not say when this is effective, the airline told Russian news agencies. Spokesmen for S7 were unavailable for comment. Separately, Ukraine Wednesday delayed a decision to introduce grain export quotas that would more than halve exports after severe weather ravaged its harvest. Ukraine plans to limit wheat exports to 1.5 million tons and barley exports to 1 million tons in September-December 2010, a draft government resolution said.