Further tests will be carried out concerning the deaths of two soldiers during SAS selection training in the Brecon Beacons.
Edward John Maher and Lance Corporal Craig John Roberts collapsed on one of the hottest days of the year while climbing south Wales' highest mountain.
An inquest at Brecon Law Courts in Powys, mid Wales, gave the medical deaths of the pair as "unascertained".
Speaking at the brief hearing was Dyfed Powys Police Detective Inspector Ieuan Wyn Jones.
He said L/Cpl Roberts had been pronounced dead on the mountain at 5.15pm, while Mr Maher died at Prince Charles Hospital in Merthyr almost three hours later.
"Post-mortems have been carried out and the causes of death are unascertained. Further investigations are being carried out," he said.
Mr Maher and L/Cpl Roberts were understood to be taking part in the aptitude training element of the course to become SAS reservists.
They were climbing Pen Y Fan, the highest mountain in southern Britain, on July 13.
L/Cpl Roberts, 24, of Penrhyn Bay, had served with the Territorial Army for around five years and is understood to have served in Afghanistan and Iraq.
Mr Maher was named as the second fatality by Ministry of Defence officials only this morning.