Speaking at a meeting of European heads of Government in Berlin, the Rt Hon Tony Blair MP said:
"I have not been commenting upto now on this because I want to get it resolved in as easy and diplomatic way as possible, because it's the welfare of the people concerned that have been taken by the Iranian Government that is most important.
"But this is a very serious situation and there is no doubt at all that these people were taken from a boat in Iraqi water, it simply is not true that they went into Iranian territorial waters. And I hope the Iranian Government understand how fundamental an issue this is for us. We've certainly sent those messages back to them very very clearly indeed.
"I hope that this can be resolved over the next few days but the quicker it is resolved the easier it will be for all of us. But they should not be under any doubt at all about how seriously we regard this act which was unjustified and wrong."
To clarify the UK Government's actions:
On 25 March 2007, Foreign Secretary Margaret Beckett spoke to Iranian Foreign Minister Mottaki. She made it clear our personnel were operating in Iraqi waters, called for their safe return and immediate consular access.
Her Majesty's Ambassador and the Deputy Head of Mission met with the Ministry of Foreign Affairs on the morning of Sunday 25 March 2007. The meeting was at our request. We again asked for the release of the detained personnel. We also asked where they were being held and for Consular access. Dialogue with the MFA is continuing.
We have been in touch with governments in the Gulf region to enlist their help in lobbying Iran for the release of the group and their equipment.
The families of the Royal Navy and Royal Marine personnel detained in Iran have stated:
"While we understand the media interest in the ongoing incident, this remains a very distressing time for all of us and our families.
"We are grateful for the support shown to us by everyone involved and appreciate it, but would request that our privacy is respected."