t1_faye_ap.jpgLONDON, England (CNN) — Britain will be allowed to make contact with 15 sailors and marines seized by Iran as soon as a preliminary investigation has been completed, an Iranian official has been quoted as saying. “After preliminary investigations are over contacts of the British embassy and consulate with the soldiers will be possible,” Foreign Ministry spokesman Mohammad Ali Hosseini told the official IRNA news agency. He did not elaborate, according to Reuters. Britain’s ambassador to Tehran has met with Iranian officials this week in a bid to get the naval personnel released. He has also asked for access to them. Iran will not disclose their whereabouts, but has said they are well. British Prime Minister Tony Blair said Tuesday his country is prepared to move to a “different phase” if negotiations fail to free those held captive. Iran’s Revolutionary Guards captured the group Friday, while it was conducting what Britain called an inspection of a merchant vessel near the mouth of the Shatt al-Arab, at the northern end of the Persian Gulf. Britain said the Royal Navy crew were seized in the Iraqi part of the waterway, where the border with Iran is disputed. Iran however says the group was in Iranian waters. In an interview on GMTV on Tuesday Blair said: “I hope we manage to get them (the Iranian government) to realize they have to release them. If not, then this will move into a different phase.” Asked what that meant, Blair said: “Well, we will just have to see, but what they should understand is that we cannot have a situation where our servicemen and women are seized when actually they are in Iraqi waters under a U.N. mandate, patrolling perfectly rightly and in accordance with that mandate, and then effectively captured and taken to Iran.” Blair’s spokesman said later the prime minister did not mean Iranian diplomats would be expelled or military action was likely. His office did say though that officials may have to make public evidence proving the Britons were seized in Iraqi — not Iranian — waters, if there is no swift release of the sailors. “We want to resolve this quickly without having a public confrontation with them, but as the prime minister said we want to resolve it. If we cannot resolve it quickly, then maybe we have to be more explicit,” said the spokesman. CNN’s European Political Editor Robin Oakley said Blair’s reference to a “different phase” intrigued many people. “Downing Street officials said Mr Blair wasn’t hinting at expelling Iranian diplomats from London or at any kind of military action,” Oakley said. “What is likely is that British authorities will shift the dialogue steadily from private exchanges to more public ones. Diplomats also expect there to be more concerted action at the United Nations if the men are not released soon. British authorities are confident that they have evidence to prove their insistence that the Royal Navy personnel never left Iraqi waters.” Earlier Tuesday, Iran said the 15 sailors and marines were healthy and being treated in a humane fashion. “They are in completely good health. Rest assured that they have been treated with humanitarian and moral behavior,” Mohammad Ali Hosseini, a spokesman for the Foreign Ministry, told The Associated Press on Tuesday. Hosseini said the one woman in the group, Faye Turney, had complete privacy. “Definitely all ethics have been observed,” he said. A file photo of Turney, taken in 2000, was released Tuesday. The official declined to say where the marines were being held and repeated that their case was under investigation. “The case should follow procedures,” Hosseini said. “Media hyperbole will not help (speed things up).” Meanwhile on Tuesday the U.S. Navy started its largest show of force in the Persian Gulf since the 2003 invasion of Iraq, led by a pair of aircraft carriers and backed by warplanes off the coast of Iran. U.S. Navy Cmdr. Kevin Aandahl told AP the maneuvers were not organized in response to the capture of the British sailors — nor were they meant to threaten the Islamic Republic, whose navy operates in the same waters. (Full story) Sailors questioned Hard-liners in Iran have urged the government to charge the 15 marines and sailors with espionage and put them on trial. No official word has emerged on whether Iran’s government will do so. But, according to AP, Iran has begun questioning the sailors and marines. “It should become clear whether their entry was intentional or unintentional. After that is clarified, the necessary decision will be made,” AP quoted Iranian Deputy Foreign Minister Mehzi Mostafavi as saying. Competing claims The group was part of a boarding party from the frigate HMS Cornwall, which was on routine patrol to prevent smuggling, Britain’s Ministry of Defense said. (Location of incident) The vessel was intercepted on suspicion of smuggling automobiles, a U.S. military official who monitors the region told CNN. The official insisted on anonymity because the incident did not involve American forces. Britain insists the group was in Iraqi waters, a claim Iraq supports; Iran insists it was in Iranian waters. Competing claims on the waterway, which provides Iraq’s only outlet to the Gulf, was one of the causes of the 1980-88 war between Iran and Iraq. (Read about the contested waterway) The incident could escalate an already fraught relationship between Iran and the West. On Saturday, the U.N. Security Council of Saturday agreed to tougher sanctions against Iran for its refusal to meet U.N. demands that it halt uranium enrichment. Many in the West fear the country’s nuclear program is not for power generation but for arms making, a claim Iran denies. (Full story) Iran’s semi-official FARS News Agency reported the same day that the captives were taken to Tehran to explain their “aggressive behavior,” and that they had confessed to trespassing into Iranian waters. This is not the first such incident. In 2004, Iran stopped three British boats and seized eight Royal Navy Sailors and six Royal Marines. The Iranian Foreign Ministry said at the time the three boats had crossed into Iran’s territorial waters, and the detained servicemen appeared on Iranian television blindfolded. They were released after Iran said it determined they had mistakenly crossed into Iran’s waters, a claim Britain never accepted. CNN’s Aneesh Raman contributed to this report. Copyright 2007 CNN. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed. Associated Press contributed to this report.