CAIRO (Reuters) - A leading member of an opposition campaign which was until this week challenging Egypt’s President Abdel Fattah al-Sisi in upcoming elections was attacked outside his home on Saturday in what his lawyer described as a failed kidnap attempt.

Hisham Genena, a former anti-corruption watchdog chief, had been working to elect former military chief-of-staff Lieutenant General Sami Anan, the last challenger seen as a potential threat to the re-election of Sisi in polls slated for March.

Anan’s campaign was abruptly halted after he was arrested this week and accused of running for office without military permission.

Anan’s family said late on Saturday that he is being held at a military prison, without providing any details.

His lawyer, Nasser Amin, said on his Twitter account that he had visited his client there.

Genena had just left his home in a suburb outside Cairo when two cars stopped him and a group of men attacked with knives and sticks, Anan’s spokesman, Hazem Hosny, told Reuters.

Security sources said the alleged attackers were questioned at a police station along with Genena just after the incident.

The Interior Ministry could not be immediately reached for comment.

Pictures later posted on social media and verified by Genena’s family show him with a badly battered eye and a blood-soaked bandage wrapped around his knee.

His lawyer, Ali Taha, told Reuters that Genena was taken to a hospital to be treated for a bleeding eye and several fractures.

“It was a failed kidnapping attempt..(it) was stopped when bystanders interfered,” said Taha.

“They were trying to kill him,” his wife, Wafaa Kedieh, told Reuters.

As Egypt’s top auditor, Genena had stirred controversy by publicly concluding that government corruption had cost the country billions of dollars. He was sacked by Sisi in 2016.

Last week an army statement read on state TV said Anan’s presidential bid amounted to “a serious breach of the laws of military service” because as a military officer he was required to end his service and get permission before seeking office.