Washington (AFP) - US President Barack Obama on Monday met Washington Post journalist Jason Rezaian, who spent 18 months in an Iranian prison before his release in January.

The White House said that Obama "had an opportunity to meet briefly" with Rezaian‎ after delivering remarks at the State Department.

Rezaian was among four prisoners freed in Iran hours before world powers began implementing a deal with Iran on its nuclear program.

In return, the US pardoned seven Iranian prisoners and dropped charges against 14 other Iranians.

Obama's earlier address to US ambassadors and heads of mission was heavily focused on the benefits of diplomacy.

In the face of fierce criticism, Obama has made diplomatic engagement with adversaries a hallmark of his foreign policy.

Securing the release of Rezaian -- along with Christian pastor Saeed Abedini, former US Marine Amir Hekmati, and Nosratollah Khosravi-Roodsari -- is seen by the White House as a vindication of that stance.