Iran and Venezuela signed a 20-year cooperation plan on Saturday, according to live coverage by Iranian state television.
The plan includes cooperation in oil, petrochemicals, tourism and culture.
The signing ceremony was held at Saadabad Palace in northern Tehran, attended by Venezuelan President Nicolas Maduro and his Iranian counterpart Ebrahim Raisi.
During his first visit to Iran, Maduro said Tehran had helped his country by sending badly needed fuel despite US sanctions and threats.
In an interview with Maduro on Friday evening after his arrival, Iranian state media reported that Maduro had welcomed Iran’s decision to send tankers to his energy-hungry country.
“The delivery of oil from Tehran to Caracas has been a great help to the Venezuelan people,” he said.
A high-ranking political and economic delegation from Venezuela, which like Iran is under heavy US sanctions, is accompanying Maduro on the two-day visit, at an invitation from Raisi.
Maduro said Venezuela and Iran are united by “a common vision” regarding international issues and are both victims of coercive measures by the United States and its allies.
“Caracas and Tehran have shaped the strategy of (a) resistance economy and are working to expand it,” he said.