Iran also sent a letter to the British embassy in Tehran on Saturday complaining about shots fired by British troops near its consulate in the southern Iraqi city of Basra.
Iran previously accused British forces of surrounding the consulate on Thursday and firing into the air in a provocative act. The British military denied any aggressive action.
Iran's ISNA news agency on Sunday quoted a foreign ministry official as saying: "Iran asked Britain to prevent any such actions from happening again and asked for the British soldiers in Iraq to respect international regulations applied to diplomatic places".
The British military said the shots heard came from a British convoy that was ambushed in the same street as the consulate in central Basra.
Weighing into the growing international row on the capture of the Royal Navy sailors for the first time, George Bush, the US president, on Saturday demanded Iran release the sailors.
"It is Iran's responsibility to find a quick solution"
Emkay, Auckland, New Zealand
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Bush, at a news conference, said: "I support the Blair government's attempts to resolve this peacefully. And I support the prime minister when he made it clear there were no quid pro quos. The Iranians must give back the hostages.
"The British hostages issue is a serious issue because the Iranians took these people out of Iraqi water, and it's inexcusable behaviour."
Ali Reza, Al Jazeera's correspondent in Tehran, said Bush's use of the term "hostages" will likely further infuriate Mahmoud Ahmedinejad, Iran's president, who has labelled Britain as "arrogant" for failing to apologise.
Reza said: "Demands from the European Union that they are freed immediately and unconditionally, are only antagonising the situation".
Mohammad Ali Hosseini, a spokesman for the Iranian foreign ministry, said: "The recent stance of the European Union officials regarding this issue will not help in solving the problem, but instead it will complicate the issue and might even make it last even longer."
And after Iran's ambassador to Russia said the 15 could be tried for violating international law, Britain confirmed on Saturday it had sent a letter of response to accusations of "trespassing" in Iranian waters.
Terry Waite, who was held captive for almost five years in Lebanon the country's civil war, has offered to his services to help settle the issue.
Speaking to Al Jazeera on Saturday, Waite said: "I would hope that the Iranians would behave in the same courteous way to me as they've behaved before, would perhaps give me access to the people they've detained just to be assured of their welfare, so that that could be conveyed to their families, and begin to see if we can find a sensible way through this problem."
However, Reza reports, Tehran is remains defiant that what the sailors did was wrong, that they have confessed to their actions, and foreign interference will achieve little to secure the sailors' release.