NEW YORK — 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 says.

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. China’s foreign ministry referred a question about its executions last year to the justice ministry, which did not respond to phone or fax.

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. The group said Iraq executed at least 169 people.

Executions in chaotic Syria and Egypt could not be confirmed.

Amnesty International is blunt about its stance on the issue. “We oppose the death penalty in all cases, without exception,” Jose Luis Diaz, the group’s representative at the United Nations, told reporters Wednesday. “It is the ultimate cruel, inhuman and degrading punishment.”

He also criticized this week’s sweeping decision in Egypt, which he called “in recent history the largest number of death sentences handed down by a court at a single instance.”

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

Amid the bleak numbers, the rights group pointed out that a small number of countries — about one in 10 — carry out executions, and 140 countries are against the death penalty either in law or actions.

“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.

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.

But the rights group was alarmed by four countries that resumed executions after a pause of a year or more: Indonesia, Kuwait, Nigeria and Vietnam.

The report also objected to “‘confessions’ that were possibly extracted through torture of other ill-treatment,” and it said the proceedings in a majority of countries that executed people or sentenced them to death “did not meet international fair trial standards.”

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.”

The report listed the countries where public executions were known to occur: Iran, North Korea, Saudi Arabia and Somalia.

And it listed the known methods of execution, including beheading in Saudi Arabia, electrocution in the United States and lethal injection in China, Vietnam and the United States. Several countries were listed as using hanging and shooting.

The report said there were no reported executions last year by stoning.