The U.S. military on Monday put off hearings in the Guantanamo war crimes tribunals at least until July, meaning they will not reconvene until after an expected ruling by the U.S. Supreme Court on their legitimacy.

The U.S. Supreme Court is due to rule by June 30 on the legitimacy of the military courts that President George W. Bush created to try suspected terrorists after the September 11 attacks.

The Pentagon had already suspended the tribunals indefinitely after three Guantanamo prisoners were found hanged in their cells in apparent suicides on June 10. Pretrial hearings scheduled last week and this week were put off.

On Monday, tribunal lawyers were notified specifically that hearings scheduled June 26-July 7 for Canadian prisoner Omar Khadr were also put off.

Khadr, 19, is charged with murdering a U.S. soldier in a firefight in Afghanistan and is one of 10 Guantanamo prisoners charged with war crimes in the tribunals.

Security forces needed to hold the tribunal hearings at the remote U.S. naval base in Cuba were busy with the investigation into the detainees’ deaths, said Maj. Jane Boomer, a Pentagon spokeswoman.

The deaths prompted a new round of calls from U.S. allies, critics and rights activists to shut down Guantanamo, where about 460 suspected Taliban and al Qaeda prisoners have been held without trial, some for more than four years.

Bush has acknowledged that Guantanamo is seen by some countries as an example of U.S. failure to uphold the human rights values it espouses and said he wanted to close it.

“I’d like to close Guantanamo, but I also recognize that we’re holding some people there that are darn dangerous and that we better have a plan to deal with them in our courts,” Bush told a news conference last Wednesday.

The tribunals are the first held by the U.S. military since World War Two. They had convened regularly since January for preliminary hearings aimed at getting some of the cases ready to begin trials soon after the Supreme Court rules.

Monday’s announcement formally cleared the tribunal calendar until a next round of hearings, set for July 24.

“Looking into the crystal ball, we’re probably unlikely to do anything before the 24th of July,” said Marine Col. Dwight Sullivan, chief defense counsel in the tribunals.