The founder of an anti-Israel boycott movement says the Israeli authorities' investigation into his suspected tax evasion is based on "vicious lies."

Omar Barghouti, a Palestinian who holds Israeli residency, says Saturday he is not allowed to delve into details of his case because of a gag order. But he insists the probe is politically motivated.

The Israel Tax Authority says Barghouti is suspected of evading taxes between 2007-2017 on $700,000 in income from managing a cash machine business, and on income from lectures around the world and royalties on a book.

Barghouti is a founder of the BDS movement advocating boycotts, divestment and sanctions against Israel. Supporters say BDS is a nonviolent movement for Palestinian independence, but Israel says it aims to delegitimize the Jewish state.