Thousands of people were sentenced to death in the country, although exact figures remain unknown because such killings are kept a state secret, the report said.
Iran, Saudi Arabia, Iraq and Pakistan were also named as notable users of capital punishment. Together, the three countries executed more than 830 people.
But the report, released on Thursday, also highlighted an overall global decline in death penalties. Excluding China, some 993 were carried out in 23 countries in 2017 – down four per cent from the previous year and 39 per cent from 2015.
Some 2,591 death sentences – not necessarily yet carried out – were recorded in 53 countries, down from 3,117 the year before, the London-based human rights organisation said.
And it particularly praised sub-Saharan Africa as a “beacon of hope”, highlighting the fact 20 countries in the region had now abolished the death penalty. Just two states there – Somalia and South Sudan – carried out executions last year.
With such progress, "the isolation of the world's remaining executing countries could not be starker," said secretary general Salil Shetty.
But the organisation said it would like to see the numbers come down even further.
It said the continued use of the death penalty for drug-related offences in countries including Singapore and Malaysia was “distressing”. And it drew attention to how the US, Japan and the Maldives had all placed people with “mental or intellectual disabilities” on death row.
Some countries, it noted, had resumed use of capital punishment in 2017, including Bahrain, Jordan, Kuwait and the United Arab Emirates.
Worldwide at least 21,919 people are known to be awaiting a death sentence. Amnesty International said: "Now is not the time to let up the pressure."
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