TEHRAN, Iran (AP) – Iran’s ambassador to Russia renewed a threat Iranian officials made earlier this week, saying 15 British sailors held by Iran could be tried for violating international law, Iran’s state news agency IRNA reported Saturday.

Gholam-Reza Ansari told Russian television Vesti-24 on Friday that Iran had launched a legal investigation of the British sailors. “They will be tried if there is enough evidence of guilt,” Ansari was quoted by IRNA as saying.

Britain’s Foreign Office said it was checking the claim that the sailors were facing trial, but noted that the ambassador’s comments didn’t alter their view of what was needed to resolve the standoff.

“This doesn’t change our position, we have made it perfectly clear that our personnel were in Iraqi waters and we continue to request immediate consular access to them and their immediate release,” said a spokeswoman for Britain’s Foreign Office, speaking on customary condition of anonymity in line with government rules.

Mr. Ansari’s talk of the sailors and marines possibly being tried echoes comments made earlier this week by Ali Larijani, the main negotiator in Iran’s foreign dealings.

If Britain continued its current approach to the standoff, Mr. Larijani told Iranian state radio, “this case may face a legal path. British leaders have miscalculated this issue.”

Earlier, Iranian Foreign Ministry spokesman Mohammad Ali Hosseini had said the case was following normal procedures, holding out the possibility that the Britons could be brought to trial.

Mr. Ansari also reiterated Iran’s stance that the British government could resolve the crisis by admitting the sailors entered Iranian waters.

“If the U.K. government admits its mistake and apologizes to Iran for its naval personnel’s trespassing of Iranian territorial waters, the issue can be easily settled,” he said.

The diplomat claimed the British government had escalated the crisis by taking the matter to the U.N. Security Council rather than resolving it on a bilateral basis.

Britain has frozen most contacts with Iran and referred the issue to the U.N. Security Council, which expressed “grave concern” on Thursday over Iran’s seizure last week of the Britons.

The British sailors were detained by Iranian naval units March 23 while patrolling for smugglers near the mouth of the Shatt al-Arab, a waterway that has long been a disputed dividing line between Iraq and Iran.

Iran appears intent on sending a message of strength as it faces mounting U.N. Nations sanctions over its uranium enrichment program, which the U.S. and other nations suspect the Islamic Republic is using to develop nuclear weapons.

On Friday, a captive Royal Marine was shown in new TV footage apologizing for being in Iranian waters, and Tehran made public a third letter supposedly written by the only woman prisoner among 15 Britons seized by Iran’s Revolutionary Guards, Faye Turney.

Britain sharply denounced Iran over the treatment of the captives – a clear sign both sides were hardening their stance as the crisis entered its second week.