The US government only acknowledges its role in targeted killings in general terms, refusing to take responsibility for individual strikes or provide casualty figures, including civilian deaths, Human Rights Watch said in their report on drone attacks in Yemen
The Yemeni authorities have been almost as silent, the rights organisation said. Both governments have declined to comment on the six strikes that Human Rights Watch investigated.
More top news
The Labour leader said socialist politics would not be put "back in a box" as he appeared on stage at the festival.
There are reports that at least some MPs and Lords have been left unable to access their emails as a result of the attack.
Cuillin, six, and four-year-old Lejla designed the memorial plaque to their mum that has been installed in the Commons chamber.