March 28 (Bloomberg) -- The U.K. Ministry of Defence, stepping up pressure on Iran to return 15 detained sailors and Marines, released evidence suggesting British boats were 1.7 nautical miles inside Iraq when they were seized.

Vice Admiral Charles Style said Iran's navy raided Britain's boats on the Iraqi side of the Shatt al-Arab waterway dividing the two countries on March 23. He said GPS navigation data showed the position of Britain's boats, adding that Iranian officials have given two separate accounts of the location of the vessels.

``It is hard to understand a legitimate reason for the change of coordinates,'' Style said at a briefing in London today. The boats, he said, were about their ``legal business in Iraqi waters under a United Nations'' resolution.

The comments marked an escalation in the diplomatic effort, bringing details of the British argument with Iran into the public. Prime Minister Tony Blair, who has attempted to defuse the situation by giving time for private discussions between British and Iranian officials, today told Parliament that the capture of the Britons was ``wrong and completely illegal.''

``We had hoped to see their immediate release. It is now time to ratchet up the pressure,'' Blair said.

Iran rejected the British assertions, saying the boats were half a kilometer (0.3 of a mile) inside Iranian waters. A statement from the Iranian embassy in London said the sailors and Marines were in good condition and that an investigation into the matter was underway.

`Confident of Resolving'

``We are confident that Iranian and British governments are capable of resolving this security case through their close contacts and cooperation'' in a way that would prevent the ``reoccurrence of such incidents in the area,'' the embassy said. ``We are of the belief that this legal and technical issue has no link to any other issues.''

Yesterday, Iran's Foreign Ministry raised hopes that the crisis could be resolved peacefully. ``The issue will be solved in a calm atmosphere,'' said the ministry's spokesman, Mohammad Ali Hosseini. ``We cannot predict how long it will take.''

British diplomats in Tehran will be able to contact the 15 sailors and Marines after an ``initial phase of inquiry,'' Hosseini was quoted as saying by the official Islamic Republic News Agency yesterday.

Britain has avoided threatening military action or increased economic sanctions against Iran because of the incident. Blair's stance, backed by opposition politicians, reflects his limited options to defuse the dispute and the lessons learned from previous incidents with Iran. President Jimmy Carter's effort to free 52 Americans held in Tehran in 1980 cost the lives of eight Marines and failed to recover any hostages.

Turkish Role

Turkish diplomats may meet with the detained Britons to help reassure the U.K. government that they are in good health and help defuse political tensions over their capture.

``We can expect a positive development at anytime,'' Turkish Prime Minister Recep Tayyip Erdogan told reporters at the 19th Arab League summit in Riyadh, Saudi Arabia, today after meeting with Iranian Foreign Minister Manouchehr Mottaki. ``Now the investigation process by Iran is going on. I can't give an exact time.''

The group was captured at gunpoint in the Shatt al-Arab waterway, which divides Iran and Iraq, on March 23. The U.K. says they were in Iraqi waters conducting routine inspections of merchant shipping and had finished boarding an Indian ship.

Previous Incidents

Blair's government has succeeded in freeing those held in similar situations in the past. In June 2004, Iran detained eight British servicemen for three days after capturing them in the Shatt al-Arab. Similarly, five members of staff from the British embassy in Ethiopia kidnapped in the north of the country were released after 13 days on March 13 following diplomatic talks.

Iraqi Ambassador to London Salah al-Shaikhly earlier today said his country has good relations with Iran and ``can be of some help'' in securing the release of the sailors and Marines.

``At the end of the day the voice of reason should prevail,'' he said in an interview with the British Broadcasting Corp.'s Radio 4. ``We have already said we think they were on the Iraqi side and we will do our best to bring this to a peaceful conclusion.''

To contact the reporter on this story: Mark Deen in London at markdeen@bloomberg.net; Caroline Alexander in London at calexander1@bloomberg.net.

Last Updated: March 28, 2007 07:31 EDT