Iran has more than doubled its credit line to Cuba under agreements signed Thursday to strengthen economic and trade cooperation, Cuba\'s official NNTV news reported. The Cuba-Iran protocol was signed at the end of a two-day visit here by Iranian Vice President Mohammad Reza Rahimi and includes an expansion in credit to Havana from 270 million to 680 million U.S. dollars. The protocol also included collaboration accords on industry, energy, trade, health, finance, biotechnology and hydraulics. Rahimi met Cuban leader Raul Castro Thursday morning, according to an official statement. During the meeting, both leaders \"discussed the excellent state of bilateral relations and the willingness to work towards strengthening the economic and trade collaboration,\" the statement said. Rahimi also conveyed greetings from Iranian President Mahmoud Ahmadinejad to Castro. Iran has been producing equipment for rail systems and synthetic media for the Cuban market under a 2009 agreement and the latest expansion of credit is to support the continuence of that program. Iran and Cuba always support each other in internatonal affairs. Havana defends Iran\'s right to use atomic energy for \"peaceful purposes,\" while Teheran condemns the U.S. economic blockade agaisnt the Caribbean island nation.