Former South Korean military strongman Chun Doo-hwan, who seized power in a 1979 coup and brutally crushed pro-democracy protests before going to prison for misdeeds while in office, has died at the age of 90.

Chun, who had suffered in recent years from Alzheimer’s disease and a type of blood cancer, had a heart attack and was declared dead at his home in Seoul, police and officials said.

Chun’s rule lasted until 1988 and remains for many South Koreans a time marked both by severe political repression and rapid social and economic changes.

His coup came just two months after the assassination of his mentor and army leader, General Park Chung-hee, who had held power since the 1960s. Park was assassinated by his own intelligence chief after a harsh 18-year rule.

South Koreans suffered human rights abuses during these two dictatorships, but the country’s economy grew dramatically from the ruins of the 1950-53 Korean War. South Korea now ranks as Asia’s fourth-biggest economy.

Chun was an army major-general in December 1979 when he seized power, which he quickly consolidated by launching a bloody crackdown on a civil uprising in Gwangju. Government records show that around 200 people died, but activists said the death toll was much higher. Tens of thousands of others were imprisoned.

Chun’s military tribunal arrested prominent opposition leader Kim Dae-jung and sentenced him to death for allegedly fomenting the Gwangju uprising. After the US intervened, Mr Kim’s sentence was reduced and he was eventually freed. He later became president and won the 2000 Nobel Peace Prize for his efforts to promote democracy and reconciliation with North Korea.

Despite political oppression, South Korea’s economy boomed during Chun’s tenure. He introduced several liberalising measures, including an easing of restrictions on overseas trips. South Korea also won the rights to host the 1988 Summer Olympics.

Many conservatives still view Park as a hero who pulled the country up from poverty, but for most people Chun is a highly negative figure, mainly because of the Gwangju crackdown. Chun never apologised and refused to acknowledge that he was behind orders to fire on demonstrators.

Last month, Chun’s army friend and another former president, Roh Tae-woo, who played a key role in the 1979 coup, died at the age of 88.

Jang Seung-Jin, a professor at Seoul’s Kookmin University, said it was “very regrettable” that both leaders died without apologising for the crackdown.

He added that South Koreans remain divided over the legacy of their past military rulers.

“The only reaction I had to the news of his death was ‘wow, he’s finally gone’,” said Byun Hye-min, an office worker in Seoul. Byun noted there was still a lot of anger about “the things he did and his refusal to apologise”.

Public anger over his dictatorship led to street protests in 1987, forcing Chun to accept the introduction of direct presidential elections, which were considered the start of South Korea’s transition to democracy.

Roh, the governing party candidate, won a hotly contested December 1987 election, largely due to a splitting of the vote between liberal opposition candidates Kim Dae-jung and his chief rival, Kim Young-sam.

After Roh left office in 1993, Kim Young-sam became president and, as part of reform efforts, brought both Chun and Roh to trial. The two former presidents were convicted of mutiny and treason over the coup and the Gwangju crackdown, as well as corruption. Chun was sentenced to death and Roh to 22 and a half years in prison.

Kim Young-sam eventually pardoned the two in late 1997 at the request of then president-elect Kim Dae-jung, who sought greater national reconciliation.

Park Kyung-mee, spokeswoman for President Moon Jae-in, expressed condolences to Chun’s family, but added that it was regrettable the former leader had failed to apologise for Gwangju before his death.

Chun “should have cooperated with the truth-finding efforts, expressed remorse and offered an apology, not only to Gwangju citizens, but to all of our people,” said Jo O-seop, a governing party lawmaker from Gwangju.