A sharp rise in the number of executions reported in Iran is raising suspicions that the Tehran regime has, in the words of a British newspaper, engaged in "a judicial killing spree" to intimidate its opponents.

Human rights organizations say this underlines the alarm within the regime that Iran could be infected by the wave of pro-democracy uprisings that have swept the Arab world since January and toppled three dictators.

The Tehran regime has cracked down hard on political dissidents since a major confrontation with protesters during the hotly disputed 2009 presidential election when Mahmoud Ahmadinejad won a second four-year term.

Thousands of dissidents were arrested and reportedly continue to be harassed and persecuted.

Amnesty International said there were 253 reported executions in the first six months of 2011, with another 300 people believed to have been killed. These included the first executions of juvenile offenders in the world this year.

In February, Shirin Ebadi, an Iranian human rights activist and former judge awarded the Nobel Peace Prize in 2003, accused Tehran of using criminal charges, narcotics in particular, to mask executions for political purposes.

"A second-term presidency launched amid bloodily suppressed riots in 2009 now appears to be assuming an even more vicious character as reports accumulate of ongoing secret mass executions and new waves of political repression," foreign affairs columnist Simon Tisdall wrote in The Guardian of London recently.

These events "suggest the regime is embarked on what is in effect a judicial killing spree," he wrote.

There was a sharp rise in the number of executions last December and January. The United Nations reported that 66 people were executed in Iran in January.

Most were reportedly related to narcotics crimes but three political activists arrested in 2009 were among those hanged, the office of the U.N. Commissioner for Human Rights reported.

"It's no coincidence that Iran's increased staging of public executions came at the same time protest movements were gaining steam throughout the Middle East," Mark Wallace, a former U.S. ambassador wrote in the Los Angeles Times recently.

"What better way to keep Iranians from having 'dangerous ideas' like those of their neighbors?"

The United Nations says executions in Iran in the early part of the year were running at three times the rate of 2010 when about 18-25 people were executed monthly. The United Nations estimated that about 300 executions, most of them undeclared, took place in 2010.

Iran Human Rights, an independent monitoring organization, reported that 25 people were executed in Ghezel Hesar Prison in Karaj, 25 miles west Tehran, July 3, with another seven in Tehran's notorious Evin Prison. All were allegedly drug-related.

Another frenzy of executions was reported two months later in the same two prisons. The state-owned newspaper IRAN said 22 men convicted of drug trafficking were hanged Sept. 19 in Evin and Ghezel Hesar.

Iran Human Rights said it had uncorroborated evidence that mass executions took place during 2010 in prisons in Khorasan province in northeastern Iran.

The International Campaign for Human Rights in Iran, a non-governmental group, reported in 2010 that undeclared mass executions had taken place in Vakilabad Prison in Mashhad, one of the holiest cities in Shiite Islam.

Ten prisoners were reported to have been hanged there Oct. 12, 2010. ICHRI quoted a former inmate as saying he'd witnessed 49 executions in one day in October 2009.

Mashhad, 530 miles east of Tehran, is the capital of Razavi Khorasan province. It's a smuggling center for opium and heroin from neighboring Afghanistan.

Iran is a key conduit for large volumes of narcotics from Afghanistan and Pakistan headed westward through Turkey to Europe.

Narcotics use is alarmingly high in Iran and eradicating it has become a national priority. Some 3,500 security officers have been killed fighting smuggling gangs over the last two decades.

In 2010, amid growing criticism of Iran in the West for the growing number of executions in prison, the spokesman of Iran's Foreign Ministry, Ramin Mehmanparast denounced the West for its condemnation.

He claimed 80 percent of those hanged were drug smugglers and declared, "If Iran does not combat drugs, Europe and the West will be hurt."