Iraq executed almost twice as many people last year compared to the year before, while India and Pakistan resumed executions after abandoning the practice for years, global human rights group Amnesty International said on Tuesday.
In its annual report, Amnesty said China still led the top five countries carrying out executions, followed by Iran, Iraq, Saudi Arabia and the United States.
Despite setbacks in several countries, the group said it was encouraged by overall signs of progress in the global trend toward ending the death penalty.
In the US, nine states carried out executions in 2012, compared to 13 in the previous year.
"In many parts of the world, executions are becoming a thing of the past," said Salil Shetty, Amnesty's secretary-general. "Only one in 10 countries in the world carries out executions. Their leaders should ask themselves why they are still applying a cruel and inhumane punishment that the rest of the world is leaving behind."
Amnesty, which opposes the death penalty without exception, counted 682 confirmed executions in 21 countries in 2012, two more than the tally in 2011, and said at least 1,722 people were known to have been sentenced to death in 58 countries last year.
That figure does not include the number of executions in China, which executes more people than any other country but keeps the data strictly secret.
Human rights activists estimate the annual figure at 6,000 to 8,000, but Amnesty stopped publishing estimates on executions in China in 2009 because of the lack of reliable data.
Hao Xingwang, a criminal law expert at Beijing's Renmin University, believed that the number of executions would likely continue to fall as Beijing tightens its regulations. Public support for the death penalty, however, would remain strong for some years, he said.
"Most Chinese people believe the death penalty is necessary, but don't really understand the risks and drawbacks. The concept of an eye-for-an-eye has been well established since ancient times and will take a long time to change,'' Hao said.
Iran came second on Amnesty's list, with 314 officially confirmed executions, though the organisation said the actual number was almost certainly higher.
The group said it was gravely concerned by developments in Iraq, which executed 129 people last year, almost double the 68 executions it carried out in 2011.
Most of those sentenced to death in Iraq were convicted in terrorism-related cases.
"Many trials of those sentenced to death failed to meet international standards for fair trials, including the use of 'confessions' obtained under torture and other ill treatment," said the report.
Defendants described how they suffered, for example, with being beaten with cables, burned on the face with cigarettes and given electric shocks to the hands.
In Asia, India carried out its first execution since 2004 when it put Ajmal Kasab, the Pakistani gunman convicted in the 2008 Mumbai attacks, to death in November. Pakistan also saw its first execution since 2008.
The US executed 43 people in 2012, the same figure as in the previous year. A total of 77 new death sentences were imposed, the second lowest since the Supreme Court revised capital punishment laws in 1976, Amnesty said.