Afghan President Hamid Karzai left on Thursday for neighbouring Iran to attend a regional conference, his office said.
Mr Karzai will deliver a speech to the meeting, the fourth to be held between the tripartite group of Afghanistan, Iran and Tajikistan, which share a language and Persian culture.
The Western-backed Karzai will hold talks with Iranian President Mahmoud Ahmadinejad and supreme leader Ayatollah Ali Khamenei, aiming to building stronger ties between the countries, Karzai’s office said in a statement.
Kabul has good relations with Tehran despite being heavily reliant militarily and financially on the US, which has been at loggerheads with Iran for decades.
Secret US military documents posted on whistleblower website WikiLeaks suggest that Iran provides hefty support to insurgents fighting US-led troops in Afghanistan. Mr Ahmadinejad has denied the allegations.