The UK has said it shares Iran's desire for a diplomatic solution to the crisis over 15 captured Royal Navy personnel.
Ali Larijani, of the Supreme National Security Council, said Iran's priority was to use diplomatic channels, not putting the crew on trial.
The Foreign Office said it was still studying his remarks, made to Channel 4 News, but shared his preference for bilateral discussions.
It said it would be following up his comments with Iran on Tuesday.
A Foreign Office statement said: "There remain some differences between us, but we can confirm we share [Mr Larijani's] preference for early bilateral discussions to find a diplomatic solution to this problem.
"We will be following up with the Iranian authorities tomorrow, given our shared desire to make early progress."
Speaking through an interpreter, Mr Larijani insisted the Iranians were "100%" sure of their case and warned the "language of force" from the UK and its international allies was causing problems.
"Definitely our priority would not be trial, except that the UK government would be insisting on not solving the problem through diplomatic channels," he said.
"Our priority is to solve the problem through diplomatic channels. We are not interested in having this issue get further complicated.
"I believe there should be a delegation to review the case, to clarify... whether [the captured crew] have been in our territorial waters or not."
He said the sailors and marines had been in Iranian territorial waters when captured in the northern Gulf on 23 March and "a guarantee must be given that such violations will not be repeated".
Earlier Iran said all 15 personnel had been filmed admitting they were in Iranian territorial waters at the time.
Arthur Batchelor was among those shown in the latest Iranian footage
The UK insists they were in Iraqi waters after returning from searching a merchant vessel.
However, Iranian state radio said the new footage would not be broadcast on TV because of "positive changes" in the UK's stance.
Previously unseen images of some of the crew, based on HMS Cornwall, were aired on Monday but their voices could not be heard.
One of those seen for the first time was 20-year-old Arthur Batchelor, whose sister, Maggie Phillips, told the BBC she was relieved to see him looking "tired but fine".
UK Prime Minister Tony Blair's spokesman has said there is "a lot going on behind the scenes".
"What happens next depends on the Iranian response," he added.
UK VERSION OF EVENTS
1 Crew boards merchant ship 1.7NM inside Iraqi waters
2 HMS Cornwall was south-east of this, and inside Iraqi waters
3 Iran tells UK that merchant ship was at a different point, still within Iraqi waters
4 After UK points this out, Iran provides alternative position, now within Iranian waters
The Foreign Office said it stood by its view the crew had been detained against their will in Iraqi territory.
"We have not had consular access, we have made it quite clear they were seized in Iraqi waters, and we want them released," a spokesman said.
Defence Secretary Des Browne has confirmed the government is in "bilateral" communication with Iran over the personnel.
It is understood that one area under discussion is how future disputes over the contested waters may be avoided.
IRANIAN VERSION OF EVENTS
1 Royal Navy crew stray 0.5km inside Iranian waters
2 Iran gives set of co-ordinates to back up their claims
3 According to seized GPS equipment, the Royal Navy crew had previously entered Iranian waters at several other points
4 Iran informs Britain of the position where the crew were seized, inside Iranian waters
So far, Iranian TV has shown footage of four of the crew making statements in which they said they had been in Iranian waters.
The Foreign Office has said showing the group on TV is "unacceptable" and it had "grave concerns" over the circumstances under which any statements were made.
The first footage showed Leading Seaman Faye Turney and Nathan Summers speaking.
On Sunday, Royal Marine Capt Chris Air and Lt Felix Carman were seen explaining the incident.
On Sunday, Iranian students threw stones and firecrackers at the British embassy in the capital Tehran in protest against what they said was the "illegal entry" into their waters by the UK personnel.