SEOUL, Nov. 8 (Xinhua) -- A former close aide to South Korean President Park Geun-hye has testified to prosecutors that he leaked confidential documents to Park's long-time confidante Choi Soon-sil under the president's instructions, local media outlets reported on Tuesday.

Jeong Ho-seong, former presidential secretary in charge of handling all of documents reported to President Park, said in a questioning by prosecutors that he had delivered presidential documents to Choi under the president's direction, according to Chosun Ilbo newspaper.

Jeong, who assisted Park for about two decades, is called one of "three knobs of a door" that directly leads into the president. He is alleged to have brought classified reports to Choi on a daily basis.

The leaked documents include Park's speeches, secret contacts with the Democratic People's Republic of Korea (DPRK) under former President Lee Myung-bak, schedules for the president's overseas trip and reports for cabinet meetings, according to Yonhap news agency.

The former aide, however, denied allegations that Choi had edited the presidential documents to meddle in government affairs, saying it was part of Park's efforts to listen to various opinions, Chosun Ilbo reported.

A tablet PC, which local cable channel JTBC obtained, indicated an editing of presidential speeches as multiple phrases were marked in red, according to TV footage. The speeches included a landmark one made in Dresden, Germany, in 2014 to set out a vision for reunification of the two Koreas. Choi has denied it was her belonging.

Jeong initially denied allegations that he had leaked the classified documents, but he reversed the testimony as his mobile phones, seized by prosecutors during the Oct. 29 raid, contained his recorded dialogues with the president and Choi.

Ahn Jong-beom, former senior presidential secretary on policy coordination, has also testified to prosecutors that he received instructions from President Park and gave her reports on the donations from conglomerates to establish two non-profit foundations presumably controlled by Choi.

Ahn has reportedly helped Choi pressure 53 conglomerates into donating 77.4 billion won (68 million U.S. dollars) to the Mir and K-Sports foundations. Samsung reportedly made the largest contributions of 20.4 billion won to the cultural and sports funds.

Prosecutors raided the offices of Samsung Electronics for allegations that the company had illicitly provided finance assistance to Choi's daughter who was a former member of the national equestrian team.

Samsung is suspected of having provided 2.8 million euros (about 3 million U.S. dollars) to a company in Germany co-owned by Choi and her daughter. The 20-year-old is also alleged to have received improper favors in entering a prestigious university.

Prosecutors will bring to court the case of Choi on Nov. 19, who is suspected of peddling undue influence for personal gains and intervening in government decisions behind the scenes. The 60-year-old Choi is a private citizen without any security clearance and public position.

In addition to charges of abuse of power and fraud filed against Choi, the prosecution was quoted by local media as saying that it will investigate further wrongdoings, including bribery and influence peddling, for possible indictments later on.

All of 53 conglomerates, which made donations to the Mir and K-Sports foundations, will also be investigated by prosecutors. Chairmen of the conglomerates could be summoned for questioning if necessary.

The prosecution's special investigative unit in charge of probe into the Choi Soon-sil case launched an investigation on Monday into President Park's closed-door meetings with seven of the conglomerate chiefs held in the presidential office in July last year.

Public attention is centered on whether the embattled president would be investigated over the political scandal. Park said in her address to the nation last Friday that she would accept a direct probe into herself "if necessary."