British Prime Minister Tony Blair said Tuesday that the next two days would be "fairly critical" in the bid to secure the release of the 15 captured British sailors.
"The next 48 hours will be fairly critical," Blair told the Real Radio based in Glasgow, southwest Scotland.
"I've read the transcripts of the interview Ali Larijani gave and that seems to offer some prospect but the most important thing is to get these people back." Blair said.
On Tuesday, Iran's chief nuclear negotiator Larijani told Iranian state television that Britain has started talks with Tehran on resolving the standoff over the capture of 15 British sailors.
It is "only at the beginning," he said, "things can change and we could go towards an end of this issue if they continue on this path."
Larijani on Monday has said Iran's priority is to resolve the problem through proper diplomatic channels, and "there's no need to have a trial on the detained sailors."
Hopes have risen over the possible release of the personnel as Iran claimed British diplomats had begun talks with the Foreign Ministry in Tehran.
Blair said, "All the way through this we've really had two tracks on this; one is to make sure Iran understands that the pressure is there available to us if this thing has to be hard and tough and long.
"On the other hand, to say all the way through we're not looking for confrontation over this and actually the most important thing is to get the people back safe and sound and if they want to resolve this in a diplomatic way the door is open," he added.
The 15 British naval personnel were seized on March 23 by Iranian forces when they were patrolling off the Iraqi borders. Iran has insisted that the British boats illegally entered its territorial waters. But Britain said its soldiers were in Iraqi territorial waters.