United States
The “Great Satan” remains one of Iran’s major enemies. The future tone of the relationship will be set in the November US presidential elections – in which Iran is a critical point-scoring issue. Barack Obama favours “tough diplomacy” rather than military action, while John McCain has mocked him for underestimating a “serious threat”.
Israel
Post-revolutionary Iran has never recognised “the Zionist entity”, and Mahmoud Ahmadinejad has called for Israel to be “wiped off the map”. An Israeli military exercise in June 2008 was widely seen as a warning that Israel was willing to carry out a pre-emptive strike against a nuclear Iran.
Russia
The main obstacle to the US in its attempts to create a united front against Iran, Moscow has established strong trade and diplomatic links with Tehran. While Russia publicly rebukes Iran for its nuclear ambitions, in private it provides technical assistance to the Bushehr nuclear plant.
Iraq
Following the fall of Saddam Hussein’s Sunni regime, relations between Iran and the Shia-dominated government of Nouri al-Maliki have been close – a source of concern for Iraq’s Sunni-minority leaders, many of whom believe Iran is covertly arming Shia militia groups.
Syria
The alliance between Iran and Syria was cemented by mutual antipathy to Saddam Hussein’s Iraq. But ties with Iran, which is Persian and Shia-dominated, increasingly threaten to isolate Syria from its neighbours, which are predominantly Arab and Sunni. If Israel offers incentives such as the return of the occupied Golan Heights territory, the Syrian president, Bashar al-Assad, may sideline relations with Tehran.
China
A relationship shaped by mutual economic need – the soaring energy consumption of China’s 1.3 billion-strong population and Iran’s appetite for consumer goods – the tacit alliance between Beijing and Tehran threatens US leverage over Iran. China, a veto-holding member of the UN Security Council, has weakened UN resolutions against Iran in the past.
Lebanon
Although Iran helped to establish the militant Shia group Hezbollah, which dominates Lebanon’s southern border with Israel, it claims to have ceased its support for the militia. But when civil strife broke out in Lebanon this year, many, including the Sunni regional superpower Saudi Arabia, blamed Iran for arming the militant group.