Singapore hanged a prisoner on Wednesday after he was convicted of a drugs offence, the 12th execution in the Asian city-state since last year.
It is one of several dozen countries, including the United States, China, Iran, Egypt and Saudi Arabia, that continue to put prisoners to death.
At least 579 people were put to death in 18 countries in 2021, 96 more than in the previous year, rights group Amnesty International says.
But the uptick followed six years of marked decline in the number of executions.
"Although the global trend remains unmistakably in favour of abolition, the recorded increases in 2021 should act as a warning that it is not yet time to let off pressure," Amnesty wrote in a May 2022 report.
Three countries accounted for 80 percent of all reported executions in 2021: Iran, with 314 (up 28 percent), Egypt with 83, and Saudi Arabia with 65 (an increase of 240 percent).
Amnesty's figures do not include executions in China, believed to be the world's biggest executioner, as well as North Korea and Vietnam. The three countries keep their data secret.
A total of 108 countries had formally abolished the death penalty for all crimes by the end of 2021, according to Amnesty, up from 16 countries in 1977.
More than two-thirds have abolished it either in law or practice, with Kazakhstan, Malawi and Sierra Leone the latest nations to introduce a ban.
Executions fell 35 percent in the United States in 2021 on the previous year, with 11 people put to death in six jurisdictions.
It was the lowest number of executions in the country since 1988.
President Joe Biden's administration imposed a moratorium on all federal executions in July 2021 following a wave of controversial cases under former president Donald Trump.
Virginia became the 23rd state to abolish the death penalty in 2021, the first state from the old Confederate south to do so.
Three other states -- California, Oregon, and Pennsylvania -- have a moratorium on the death penalty, meaning they do not apply it although it remains on the statute books.
Saudi Arabia put 81 people to death in a single day in March last year, more than the 69 executed in all of 2021 and a huge leap from 2020 when 27 people were put to death.
The 314 people executed in Iran last year was the highest number since 2017 and appears to mainly be people convicted of drug-related offences, Amnesty said.
Egypt executed 22 percent fewer people in 2021 compared to 2020, with eight women among the 83 people put to death.
Amnesty said at least 2,052 death sentences were handed out around the world in 2021, an increase of 39 percent over the previous year, reversing a nearly equivalent drop in 2020 when justice systems were snarled by the Covid-19 pandemic.
