MOSCOW, June 15. /TASS/. Prolonging of collaboration between Russia and Saudi Arabia and institutionalization of the OPEC+ agreement will stabilize the prices of crude oil and stimulate growth in world economy, believes Kirill Dmitriev, the head of the Russian Direct Investment Fund.

"Russia and Saudi Arabia's decision to recommend prolongation and institutionalization of the OPEC+ agreement to the 24 leading oil producing nations is truly historic," he said after the signing of a joint communique by the Russian and Saudi Energy Ministers.

OPEC+ agreement led up to a stabilization of oil prices and a steady growth of world economy, Dmitriev indicated.

"Prolonged collaboration between Russia, Saudi Arabia and other countries will make it possible to boost investment in the energy sector for many long years ahead and will bring about predictability of oil prices for producers and suppliers," he said. "It's very encouraging for world economy growth."

Saudi Arabia and Russia reached agreement on Thursday on making the next step towards broader cooperation in the energy sector, and especially in the oil and gas industry. They also agreed to work together with all the signatories to the Declaration on Cooperation for setting up a long-term cooperation format and to invite all other major oil producers to join it.

The joint communique said the two sides also put trust in a shared responsibility of all the parties for stability on the oil market.

The sides stated their plans to support investment in the oil and gas and sector for meeting the growing demand for oil, to make up for a natural decrease of the output, and to invest in the energy sector of raising its energy-effectiveness with a parallel speeding up of technological progress and enhancing stability of world economy.