As China is adding investment to revive the "rust belt" in its northeastern provinces, Russia is also looking to boost the economy in its Far East, which brings tremendous opportunities for the two geographically adjacent regions, experts and government officials said at a high-level forum at the 4th China-Russia Expo which closed Monday.

The fourth China-Russia Expo, which concluded today in Harbin, capital of northeast China's Heilongjiang province, achieved more than 30 billion yuan worth of foreign trade contracts signed with Chinese companies.

The five-day event was hosted by the Chinese Ministry of Commerce, Heilongjiang provincial government and Russia's Ministry of Economic Development and Ministry of Industry and Trade.

Upgraded to China-Russia Expo in 2014 to focus on bilateral cooperation between China and Russia, the expo was formerly called the China Harbin International Economic and Trade Fair, an annual cooperation project between China and Russia since 1990.

Aimed to expand common ground for the building of the Belt and Road Initiative and the Eurasian Economic Union, this year's China-Russia Expo also served as a platform to strengthen bilateral cooperation and exchanges and promote the common development of countries and regions involved in the Belt and Road, according to the Expo Committee.

"The expo has built a platform for the overall bilateral exchanges and played an important role in promoting bilateral trade and economic development," said Sun Chenghai, director of the Foreign Trade Development Bureau of MOFCOM. "The Expo will not only cover the traditional areas of cooperation between China and Russia, but also pay special attention to highlight the scientific and technological innovation and cooperation, which effectively promotes cooperation in the practical areas of the two countries."

"Through the China-Russia Expo and rich business activities, we will positively promote the bilateral economic and trade cooperation, and make efforts to reach the goals made by the leaders of the two countries as soon as possible," said Popov Evgeny, an official from the Russian Ministry of Economic Development.

More than 16,000 business representatives from 74 countries and regions participated in the expo, which accommodated 2,550 booths in a total exhibition area of 86,000 square meters.

Representatives from China and Russia had exchanges in fields like trade promotion, cross-border e-commerce, modern agriculture, customs clearance, transport and logistics, resources development, electronic and mechanical innovation, culture tourism and youth exchanges.

On its 84 square-meter booth, Russia's Vi Holding Group displayed aluminum alloy continuous rolling products that were produced in the Yulian Group's industrial park in Henan province.

Since 2006, Vi Holding has invested more than $3 billion in Yulian and is China's biggest private investor from Russia.

"This is our first time to take part in the expo," said Valeri Krasnov, Vi Holding's vice-president. "China is a great investment market and we received support from both China and Russia. We believe the expo can become the platform for us to show our successful experience in China and make the Russian enterprises who want to invest here know how to do it."

"China and Russia have formed many cross-border industries in recent years and Heilongjiang also benefits from it. Heilongjiang finds confidence through the China-Russian Expo, but also finds opportunity and direction of development. It is hoped that the China-Russia Expo can build platforms for more enterprises," said E Zhongqi, the chairman of the Council for the Promotion of International Trade of Heilongjiang.