British Prime Minister Tony Blair has warned Iran that the crisis over the detained British military personnel could escalate if they are not released.
Mr Blair said the first concern of his government was the welfare of the 15 sailors and marines captured last Friday and getting them released as quickly as possible.
He said the issue was being pursued through diplomatic channels and said the Iranian government needed to understand that the servicemen had to be released.
Mr Blair stated that there was 'no justification whatever' for holding them.
He warned that if the diplomatic initiative did not work, it would move into a 'different phase'.
Mr Blair has denied that the navy personnel had been in Iranian waters when they were seized.
