Washington: The relatives of three US citizens killed in American drone strikes without trial, including Anwar Al Awlaki, a radical Muslim cleric, have decided not to appeal a federal judge’s dismissal of a lawsuit they filed against Obama administration officials.

The lawsuit sought unspecified damages against several top national security officials for the deaths from two drone strikes in Yemen in 2011; the victims also included Samir Khan and Al Awlaki’s teenage son, Abdul Rahman Al Awlaki. In April, Judge Rosemary M. Collyer of the US District Court for the District of Columbia dismissed the case, deferring to the government’s national security arguments.

In a statement, Nasser Al Awlaki, the father of Al Awlaki and the grandfather of Abdul Rahman, said he had lost faith in the US courts. The older Al Awlaki had also sought an injunction blocking the government from trying to kill his son before the drone strike, but a US district court judge dismissed that as well.

“Although the court failed to fulfil its role in this case, my family and I continue to hope that answers to our questions about why our son and grandson were killed will someday see the light of day and that there may someday be accountability for the government’s actions,” he said.

The American Civil Liberties Union and the Centre for Constitutional Rights helped bring the suit, and the rights centre said in a statement that “our system of checks and balances failed these families.”

Government officials have said that Al Awlaki was an operational terrorist who was planning attacks on Americans with Al Qaida’s branch in Yemen. They said that Khan and Abdul Rahman were not deliberately targeted.