TEHRAN, May 5 (Xinhua) -- The 23rd International Iran Oil, Gas, Refining and Petrochemical Exhibition will commence in Tehran on Sunday, Financial Tribune daily reported on Saturday.

The four-day exhibition is sponsored by Oil Ministry and its subsidiary the National Iranian Oil Company.

The show, the largest annual convention in Iran's petroleum industry, will host more than 2,000 domestic and international companies.

The event provides a good opportunity for major foreign companies and domestic producers to undertake mutual cooperation and conclude contracts in the upstream and downstream oil sectors of the country.

Last year's exhibition was attended by 800 international companies from China, South Korea, Turkey, Italy, Spain, France, Austria, Germany and Finland.