The number of known executions around the world rose almost 15 percent in 2013, and the United States was among the five countries putting the most people to death, a new report by Amnesty International shows.

The Amnesty International report released Wednesday comes shortly after a stunning decision this week by an Egyptian court to sentence to death 529 alleged supporters of the Muslim Brotherhood after a two-session trial.

The London-based rights group has called the action "grotesque."

The new report said the 778 judicial executions in 22 countries the group was able to count last year don't include the thousands of people put to death in China, where such information is a state secret.

Last year's global increase is due in part to more executions in Iran and Iraq, followed by Saudi Arabia, the report said.

The number of officially acknowledged executions in Iran was at least 369, but the rights group said "credible sources" reported 335 more.

Amnesty International said Iraq executed at least 169 people but executions in chaotic Syria and Egypt could not be confirmed, according to the report.

The number of people put to death in the United States, the only country in North or South America to carry out executions in 2013, continued to go down, the report said. It executed 39 people last year, down four from 2012. More than 40 percent were by the state of Texas.

The Amnesty International report counted more than 23,000 people on death row worldwide as of the end of 2013, the report said. It also counted at least 1,925 people sentenced to death in 57 countries last year, up from the year before.

"The overall data demonstrate that the trend is still firmly towards abolition," the report said. "Excluding China, almost 80 percent of all known executions worldwide were recorded in only three countries: Iran, Iraq and Saudi Arabia."

Both Europe and Central Asia had no reported executions, the first time since 2009, according to the report.

Executions in 2013 were recorded for crimes including adultery, in Saudi Arabia; blasphemy, in Pakistan; economic crimes in China, North Korea and Vietnam; and reportedly in North Korea for pornography, escaping to China and watching banned videos from South Korea, Amnesty International said.

"In India, Indonesia, Japan, Malaysia and South Sudan, prisoners were not informed of their forthcoming execution, nor were their lawyers and families," the report said. "In Botswana, India and Nigeria, and in some cases in Iran and Saudi Arabia, the bodies of executed prisoners were not returned to their families for burial."