LONDON — But although the number of executions was rising, fewer countries were using the ultimate penalty last year, the London-based rights group said in its annual review of death sentences and executions worldwide.
While China continues to execute more people than the rest of the world put together, Amnesty said it had reduced the number of offences facing the death penalty, abolishing its use for 13 mainly white collar crimes.
Amnesty called on Beijing to publish data on those executed or sentenced to death.
Globally, those executed in 2011 were killed by a number of methods: beheading, hanging, lethal injection and shooting.
Figures on the death penalty remained classified in Belarus, China, Mongolia and Vietnam, Amnesty noted, with little or no official data from Egypt, Eritrea, Libya, Malaysia, North Korea and Singapore.
Amnesty highlighted a significant increase in judicial killings in Iran, Iraq and Saudi Arabia last year.
Iran had executed at least 360 people, three-quarters of them for drugs offences, the report said, up from at least 252 in 2010. Saudi Arabia had executed at least 82, compared with 27 the year before.
The increase in these two countries alone more than accounted for the 149 net increase in known executions across the world.
Iraq had executed at least 68, the United States 43 and Yemen at least 41, it added.
But Amnesty said it had credible reports of at least a further 274 unconfirmed or even "secret" executions in Iran. And at least three people killed by Tehran were under 18 when they committed their crimes.
It also cited reports of four further juvenile offender executions in Iran, and one in Saudi Arabia.
While the Arab uprisings had changed the political landscape in North Africa and the Middle East in 2011, hopes that this would lead to changes to the death penalty "have yet to be realised", Amnesty said.
And although the total number of death sentences in the region fell by a third compared to 2010, actual executions increased by almost half, because of Iran, Iraq and Saudi Arabia.
Amnesty secretary general Salil Shetty remained optimistic however.
"Even among the small group of countries that executed in 2011, we can see gradual progress," Shetty said.
"These are small steps but such incremental measures have been shown ultimately to lead to the end of the death penalty.
"It is not going to happen overnight but we are determined that we will see the day when the death penalty is consigned to history."
The offences for which people had been executed or sentenced to death included adultery, sodomy, apostasy and "enmity against God" in Iran, blasphemy in Pakistan, sorcery in Saudi Arabia and the trafficking of human bones in the Republic of Congo, said Amnesty.
Some 18,750 people were under a death sentence at the end of 2011, compared to 17,833 in 2010.
But only 20 countries used capital punishment last year, down from 23 in 2010 and 31 a decade ago.
"The vast majority of countries have moved away from using the death penalty," Shetty said.
"Our message to the leaders of the isolated minority of countries that continue to execute is clear: you are out of step with the rest of the world on this issue and it is time you took steps to end this most cruel, inhuman and degrading punishment."
Amnesty said 96 countries had so far abolished the death penalty.
Nine have abolished it for ordinary crimes, 35 can be considered abolitionist in practice, having conducted no executions in the last 10 years, and 58 have retained it for ordinary crimes.