The New York Times reports: What to believe? That’s a key question in the diplomatic duel over Syria, as Russia continues to dispute evidence in a United Nations inspectors’ report that points to the Syrian government’s complicity in the Aug. 21 chemical attack on the Damascus suburb of Ghouta.

The Russians, who insist the attack was a “provocation” by Syrian rebels, dismiss the findings of the U.N. experts as “biased.” Instead they cite the report of a Lebanese-born nun who, from a hotel room in Geneva, did her own analysis of videos of the scene at Ghouta and declared them fake.

So goes another chapter in a continuing information war that has made reporting on the bloody, multisided conflict in Syria such a nightmare for journalists, and such a difficult story for their readers.

Not only has Syria become ever more dangerous for reporters — 16 foreign and 60 Syrian journalists are currently detained, kidnapped or missing in Syria, according to Reporters Without Borders — but fewer newspapers around the world have the budgets to send correspondents abroad, let alone to war zones.

Finding out the truth, and figuring out whom to believe, has become even more treacherous in a world awash in YouTube videos, tweets and rumors spread by the Internet. Sorting out the facts from the fake adds new burdens and risks to the business of gathering news.

Into this breach have stepped various human rights and other nongovernmental organizations now filling the gaps left by the these shifts and twists of the media world.

Six days before the publication of the U.N. report, Human Rights Watch released its own investigation of the Aug. 21 attack that also found evidence “strongly” suggesting that the government of President Bashar al-Assad was responsible.

Not for the first time, this kind of independent report made front-page news in the world’s newspapers, which, for the most part, were unable to confirm the facts on the ground with their own reporting.

“The NGOs are doing more and more of the investigative work that journalists don’t do — either because the media they work for is understaffed, underfunded or uninterested,” said Alfred de Montesquiou, a prize-winning war reporter for the French weekly magazine Paris Match. Reached on assignment in the Central African Republic, he cited both Human Rights Watch and Amnesty International for their work in Syria, breaking or confirming major stories, and identifying key players.

It’s a role that these organizations are ready to assume, even as they defend their main purpose, which is to be advocates for victims not only of war but of injustice, abuse or discrimination around the world.

“We do feel that as journalism has ebbed, we have a responsibility to flow,” said Carroll Bogert, deputy executive director for external relations at Human Rights Watch headquarters in New York.

Human Rights Watch works in 90 countries with a staff of about 400 people based in 60 locations, many of them, not surprisingly, ex-journalists. Its budget, all privately raised, has shot up to a current $70 million from about $13 million in 1998 — when Ms. Bogert, a former foreign correspondent for Newsweek, joined.

With these resources, Human Rights Watch continues to turn out the kind of in-depth reports, each one exhaustively vetted by lawyers, editors and experts, that are increasingly hard to find in newspapers.

But there’s a difference.

“We don’t just stop at the water’s edge of journalism,” Ms. Bogert said. “We investigate, we expose and we push for change. We are advocates.”

That last role sets human rights researchers apart from journalists but not, Ms. Bogert insisted, at the expense of their credibility.

“We don’t go into the field with a narrative,” she said. “We go with open notebooks, and open minds.”

Some nongovernmental agencies have already evolved into journalistic-type multimedia, multiplatform operations, with videos, Twitter accounts, maps, graphs, satellite imagery and staff experts in areas from health to weapons. The New York Times credited forensic work by Human Rights Watch analysts in a pivotal story that traced the trajectory of rockets used in the Aug. 21 attack.

In Syria, where it has a long history chronicling complaints of human rights abuses by the government of Mr. Assad, Human Rights Watch has the same security concerns as journalists. That means it does much its work from afar, sifting through testimony, checking back with trusted sources and authenticating videos, many of which end up being discarded.

“The reason we have impact is that we have a trusted brand,” Ms. Bogert said. “What we publish has to meet rigorous standards.”

The news release used to be the classic way for NGOs to get out their message, but that, too, is changing. Human Rights Watch, for instance, has opened space on its Web site for “dispatches” written by its researchers, offering brief and quick reactions to news events. For instance, a critical response to the Op-Ed article in The New York Times this month by President Vladimir V. Putin of Russia was posted on the Web site within nine hours, getting 40,000 hits. This past week, a detailed rebuttal of Russia’s position on the Ghouta attack, written by Ms. Bogert, ran in the Moscow newspaper Vedomosti.

“Is it journalism?” Ms. Bogert asked. “I don’t know, but it is information that people need, and that people are using.”

Ms. Bogert insisted that Human Rights Watch had no intention of taking the place of foreign correspondents who remain their essential partners. “We are not dancing on the grave of journalism,” she said, “but it is a fact that there are fewer traditional journalists working for established papers. That’s not good for us, that’s not good for them, but we are among those information providers who are filling the gap.”