The former director of Israel's Communications Ministry, Shlomo Filber, formally agreed to testify in one of several corruption investigations surrounding Prime Minister Benjamin Netanyahu, at least according to Israeli media reports on Wednesday.

Filber is a close aid of Netanyahu and a veteran member of the governing Likud party. On Sunday, he was arrested on suspicion of having provided Israel's largest telecom company, Bezeq, with government benefits in exchange for favorable media coverage of the prime minister.

Read more: 'Senior figures' in Israel's Bezeq arrested in corruption probe tied to Netanyahu

Israeli media allege, without confirmation from the police, that Filber has reached a deal with Israeli police to testify against Netanyahu in the case.

Netanyahu has denied any wrongdoing and claimed that all government decisions related to Bezeq "were made according to recommendations of expert committees and expert officials." On Tuesday, Netanyahu called the allegations part of a "campaign of persecution against me and my family that has been going on for years." 

Accusations pile up

Filber's arrest comes in the midst of a series of corruption investigations against Netanyahu, as well as his family and associates. Recently, Israeli police recommended indicting him for corruption.

Read more: Israelis protest corruption in Netanyahu's government for fourth week

Israeli media also reported that a former media adviser to the Netanyahu family had offered a promotion to a public official, trying to ensure his assistance in closing a criminal probe against Netanyahu's wife Sara.

The aide, Nir Hefetz, is suspected of having offered Judge Hila Gerstel the appointment of attorney general if she dismissed a pending case concerning Sara Netanyahu's excessive household spending.

Read more: Israel: Benjamin Netanyahu's wife faces possible corruption trial

Many opposition politicians in Israel have called on Netanyahu to resign.

Netanyahu, who has led Israel periodically for 12 years since 1996, has repeatedly denied all the allegations against him. He also intends to seek a fifth term in office in 2019's general election.

Read more: Benjamin Netanyahu dismisses calls to resign

Israeli Attorney General Avihai Mandelblit, a Netanyahu appointee, is now set to decide if the prime minister would face official charges. The process is expected to take several months.

jcg/dj (dpa, AP)