Image copyright AFP Image caption Choi previously said she had committed an "unpardonable crime"

A South Korean court has sentenced Choi Soon-sil, a friend and adviser to former president Park Geun-hye, to 20 years in jail for corruption, influence-peddling and abuse of power.

Choi was at the heart of a massive corruption scandal that led to the impeachment of Ms Park, the country's first female president.

Ms Park is standing trial for more than a dozen charges but denies wrongdoing.

A lawyer for Choi said she will appeal the sentence.

Choi was accused of using her presidential connections to pressure conglomerates - including electronics giant Samsung and retail group Lotte - to donate millions of dollars to two non-profit foundations she controlled.

"The guilt of the accused is heavy," the judge said, adding that she had capitalised on her "long private ties" with Ms Park to solicit bribes and had "meddled in state affairs widely".

The Seoul Central District Court fined Choi 18bn Korean won ($16.6m; £12m).

Ms Park is accused of colluding with Choi. She remains in custody, with a verdict expected later this year.

Choi is already serving a three-year jail term for a separate charge of corruption, after she was found guilty of using her position to solicit favours for her daughter.

Separately, the court found Shin Dong-bin, chairman of the Lotte Group, guilty of offering billions in bribes to Choi, and jailed him for two years and six months.

Samsung's vice-president had also been jailed for making donations to Choi for political influence, but he was freed earlier this month.

Image copyright AFP Image caption Park Geun-hye has been charged with bribery and abusing state power

Ms Park was officially ousted in March 2017, following parliament's decision to impeach her. She was the country's first democratically elected president to be forced from office.

After losing her presidential immunity, she was charged with bribery, abusing state power and leaking state secrets, and her trial began in May.

When the allegations first emerged, they prompted numerous mass protests in South Korea, many of which called for Ms Park to step down.

The controversy has fuelled discontent against the government, the political elite and family-run conglomerates which dominate South Korea's economy.