A Greek anarchist group attacked the Athens headquarters of Novartis on Sunday, Greek police said, amid bribery allegations against the Swiss pharmaceutical giant.
Members of the Rouvikonas (Rubicon) group broke the entry box and windows of the offices with a sledgehammer and threw red paint before they fled.
Among the 10 senior politicians reportedly named by protected witnesses in a mostly US-based investigation are conservative ex-PM Antonis Samaras, EU migration commissioner Dimitris Avramopoulos and central banker Yannis Stournaras.
They all deny wrong-doing.
The Swiss drug-maker is suspected of having bribed decision-makers and doctors between 2006 and 2015 to build a commanding position in the Greek health market, as well as secure inflated prices for its products.
Rouvikonas claimed the attack in a post on an anti-establishment website saying it came in support of those implicated because they face allegations from anonymous witnesses.
Novartis issued a statement on Sunday asking Greek authorities to denounce the Rouvikonas attack and protect the lives of its employees.