DUBAI, April 20 (Reuters) - Iran is considering attending peace talks with the United States in Pakistan, a senior Iranian official told Reuters on Monday, following moves by Islamabad to end a U.S. blockade of Iran’s ports, a major hurdle for Iran to rejoin peace efforts.

However, the official stressed that no decision had been made.

With a two-week ceasefire set to expire, a senior Iranian official said Tehran was “positively reviewing” its participation but no final decision had been made. The comments conveyed a clear change of tone from earlier statements ruling out attendance and pledging to retaliate for U.S. aggression.

The Iranian official said mediator Pakistan was making positive efforts to end the U.S. blockade and ensure Iran’s participation.

The ceasefire had appeared in jeopardy after the U.S. said it had seized an Iranian cargo ship that tried to run its blockade and Tehran vowed to retaliate.