ANTAKYA, Turkey — Despite the international outcry over recent massacres allegedly committed by backers of President Bashar Assad, statistics compiled by human rights activists show that violence in Syria has dropped since a United Nations peace plan went into effect in April and is down sharply from its peak in March.

One measure of violence, however, seems to have increased appreciably: More Syrian soldiers were killed in clashes with rebels in May than in any month since the 14-month-old uprising began.

There were also reports that arrests by Syrian security forces have increased, a violation of the U.N. plan that appears to be a major factor in the violence.

“Every day the Free Syrian Army is becoming stronger,” said Alaa Kaikooni, a fighter who referred to the rebels by the name for most of the loosely organized groups that have taken up arms against Assad.

Reliable statistics on violence in Syria are difficult to come by. There are no neutral observers collecting information there, and any death toll is suspect. The United Nations stopped trying to tabulate deaths at the beginning of the year because of the difficulties involved in verifying the numbers, and the general trend is hard to discern amid daily reports of horrific mass killings and loud denunciations from U.S. and other international officials.

But a new report listing the names of the dead and the dates on which they died, compiled by the London-based Syrian Network for Human Rights, for the first time provides a baseline for determining whether Syria is become less or more violent.

That report, which lists more than 14,000 names over 296 pages, indicates that since the U.N. peace plan went into effect in April, violence is off 36 percent from its peak and has dropped in each of the months that the plan has been in place.

Those numbers are still incredibly high – the Syrian Network for Human Rights recorded 1,344 deaths in May, including 55 noted after the report was posted on the network’s website Tuesday. Still, that’s far fewer than the 2,101 deaths the network tracked in March or the 1,610 it recorded in April. It’s lower than any month so far this year – with the exception of January, when the network reported that 1,179 people were killed – and below the monthly average of 1,616 deaths from January to May.

.Of the 14,093 people whose names are listed in the report, 8,082 died in the first five months of this year, testament to the quickening pace of violence as Assad’s opponents picked up weapons and began to attack army patrols. In contrast, 6,011 people were listed as having been killed from March 18, 2011, to the end of last year.

Even those numbers, however, understate the number of Syrians who’ve lost their lives since crowds of peaceful demonstrators began demanding change, only to be met with live gunfire by government security forces. Missing, for the most part, are the hundreds of police officers and soldiers who the Syrian government claims have been killed in rebel attacks.

According to news articles posted on the government news agency’s website, 953 police officers and soldiers have died since March 11. Of those, 404 or 42 percent, were killed in May alone.

There was no easy explanation for why the Syrian security death toll was up while the number of civilian dead appears to have declined. Last month, in a rare interview, on-duty Syrian soldiers told a McClatchy reporter that rebel forces targeted their checkpoints daily, and rebel commanders often boast of attacks on Syrian military outposts.

On Friday, rebel fighter Kaikooni, who’s in Turkey temporarily to accompany a member of his group who’d left Syria for medical treatment, received a call reporting that rebels had just taken control of another village in the country’s north.

Overall, the numbers suggest, however, that while international denunciations have increased in the wake of the executions last week of more than 80 women and children in the town of Houla, the drop in violence since the peace plan went into effect has been significant, though the level of violence remains high.

Ahmed Hassan, a Syrian human rights lawyer who’s recorded killings and arrests in the northern city of Jisr al Shughour near the Turkish border since the uprising began, said the Syrian military had been stepping up arrests since the peace plan went into effect.

“Six hundred people were arrested in Jisr al Shughour between January and March of this year, and 700 were arrested in April and May,” he said.

Activists in other parts of the country have reported an increase in arrests as well, though numbers are difficult to come by. The Syrian Network for Human Rights said it was attempting to compile a list of all those who’d been arrested, which activists say numbers in the tens of thousands.

Of the dead, 545 died after being tortured under detention, the network said.

Hassan predicted that the violence is likely to get worse the longer Assad remains in power, and other activists note that fears that it will take on an increasingly sectarian cast are growing.

The U.N. has said the killings in Houla were carried out by so-called Shabiha, a pro-government militia made up largely of Alawites, the same Shiite Muslim sect to which Assad belongs. Since the beginning of the uprising, the Syrian government has accused Sunni Muslims, who make up the majority of the country’s population, of leading the campaign to oust the president.

“Some people are fleeing villages, fearing more sectarian attacks,” said Mousab al Hamadee, an anti-government activist near Hama, a city north of Homs.

“If the international community remains silent, the violence will increase,” Hassan said. “We are heading for a sectarian war. I am very afraid. Any action has a reaction.”