South Korea's president is under investigation for pressuring conglomerates.

South Korean prosecutors raided the headquarters of Samsung Group today, as well as the nation's largest pension fund. The moves are seen as part of a broadening investigation into influence-peddling that involves South Korean President Park Geun-hye.

The Wall Street Journal described the raid as a "daylong sweep" of Samsung's headquarters in the Gangnam area of Seoul. They also raided South Korea's National Pension Service. With $460 billion in assets, NPS is the world's third-largest pension fund and is a major shareholder in many South Korean companies.

NPS cast a vote in favor of a merger of two Samsung affiliates, Samsung C&T Corp and Cheil Industries, last year. WSJ says it wasn't clear if today's raids were connected to that vote; Reuters, citing the Yonhap news agency, says there was a connection.

Park and her confidante, Choi Soon-Sil, are both being investigated over allegations that they used the president's influence to extort money from the nation's biggest companies, including Samsung, Hyundai, and LG. Prosecutors have formally accused Park of aiding in the scheme. Choi and another presidential aide were indicted on Sunday.

Park was elected to a term in office that ends in February 2018. She has refused to resign but has apologized for her actions, "saying she only sought to benefit the economy and not herself, but acknowledges carelessness in her ties with Choi," according to Reuters. She's the first South Korean president to face a criminal investigation while in office.

Samsung, NPS, and Korean prosecutors all confirmed the raid happened but did not provide further details.

It has been a difficult year for Samsung, which had to recall 2.8 million washing machines as well as 2.5 million Galaxy Note phones and then stop production of the model because of its tendency to explode.