Iran and North Korea have signed a number of cooperation agreements in science and technology.
The agreements announced on Saturday include a student exchange programme and joint scientific research on energy, environment, agriculture and food. The two countries also vowed to strengthen their united front against the United States.
Kim Yong-nam, seen as a figurehead for the North Korean state was in Tehran for the Non-Aligned Movement summit held this week.
Iranian President Mahmoud Ahmadinejad was reported as saying: "Just like North Korea, the imperialists have also put political pressure on Iran as they don't want these two states to stay independent and become powerful."
Yong Nam was quoted by the the Iranian Labour News Agency as saying that Iran had succeeded in neutralizing unspecified Western plots and had "imposed a heavy political blow on the US and its other enemies."
Leaked US diplomatic cables from 2010 showed that US officials believe Iran has acquired ballistic missile parts from North Korea.
Both countries were cited by former US President George W. Bush in his 2002 State of the Union speech as part of an "axis of evil". However, Pyongyang's Communist government and Iran's Islamic republic share little common ideology.
jm/av (Reuters, dpa)