The British top court denied permission to Wikileaks founder Julian Assange to appeal against the High Court’s decision to extradite him to the United States to face espionage charges.

U.S. authorities want Australian-born Assange, 50, to face trial on 18 counts relating to WikiLeaks’ release of vast troves of confidential U.S. military records and diplomatic cables more than a decade ago, which they said had put lives in danger.

But he could still seek to take his case to the European Court of Human Rights.