Israel's police force, accused by rights groups of improperly using powerful hacking spyware, said on Tuesday it had found "anomalies" in its electronic surveillance that meant the legality of some of its information collection was debatable.
The attorney-general's office ordered a probe into police surveillance tactics on Jan. 20, citing allegations about the Pegasus spyware produced by surveillance firm NSO Group. At the time, police said all wiretaps were conducted lawfully.
But the force's deputy chief of investigations and intelligence, Yoav Telem, told a parliamentary oversight committee that further inquiries uncovered "automatic technological anomalies."
These led to the gathering of materials "over which there is a legal debate - whether they are covered by the world of secret monitoring," a transcript published by the panel quoted him as saying.
Telem, who did not provide operational details, appeared to be alluding to Israel's 1979 Secret Monitoring Law. According to Channel 12 TV, that law empowers real-time eavesdropping on suspected criminal or terrorists - whereas Pegasus had given police added access to past communications on hacked phones.
Israel's Calcalist newspaper said in an unsourced report last month that police had used Pegasus against targets including anti-government protest leaders, sometimes without the required court warrants.
That added a new domestic angle to global pressure on Israel following allegations that Pegasus has been abused by some foreign client governments to spy on human rights activists, journalists and politicians.
NSO, whose sales are subject to Israeli government approval, says it has no involvement in any way in the system's operation once it is sold to governmental customers.
A task force set up by the attorney-general's office to investigate the allegations against police is due to submit findings on July 1.
In the interim, police said in a statement, the office had ordered it to institute "immediate measures to prevent possible straying from authorized powers." It did not elaborate on these.