A statement from the ministers, who are meeting in Bremen, Germany, also expresses "unconditional support" for Britain in the crisis and warns of "appropriate measures" if Tehran does not comply.
The EU's foreign policy chief, Javier Solana, is quoted by Reuters as saying he will try to talk to Iranian President Mahmud Ahmadinejad about the captives, who have been held by Tehran since March 23.
(compiled from agency reports)
RFE/RL Iran Report
SUBSCRIBE For regular news and analysis on Iran by e-mail, subscribe to "RFE/RL Iran Report."