Iran ? Britain demanded the safe return of 15 sailors and marines held by Irananian forces, while the rhetoric out of Tehran escalated.

Iran claimed Saturday that that the British sailors and marines had confessed to entering its waters in an act of “blatant aggression.”

The British Foreign Office summoned Iran’s ambassador for the second time in two days, saying an under-secretary had spent more than an hour in “frank and civil” talks demanding the safe return of the sailors and Royal Marines, and seeking assurances about their welfare and access to British consular officials.

Iran’s top military official, Gen. Ali Reza Afshar, said the sailors and marines were moved to Tehran and under interrogation “confessed to illegal entry” and an “aggression into the Islamic Republic of Iran’s waters.” Afshar did not say what would happen to the sailors.

Iranian Foreign Ministry spokesman Mohammad Ali Hosseini accused the British of “violating the sovereign boundaries” of Iran, calling the entry a “blatant aggression.”

The British sailors had just searched a merchant ship Friday morning when they and their two inflatable boats were intercepted by Iranian vessels near the disputed Shatt al-Arab waterway, U.S. and British officials said. The Iranians surrounded them and escorted them away at gunpoint.