By Neil MacFarquhar

New York Times News Service

In an extraordinary reversal, the Russian government dropped all charges Tuesday against an investigative reporter whose arrest had sparked widening protests.

In addition, the police officers who made the arrest will be suspended while their actions are investigated, the interior minister, Vladimir Kolokoltsev, said in a recorded statement broadcast on state television. He also asked President Vladimir Putin to fire two senior police generals: one in charge of drug enforcement for Moscow and the other the head of the capital’s western police district.

Biological, forensic, fingerprint and genetic tests had failed to turn up any evidence that the arrested reporter, Ivan Golunov, was involved with narcotics, as police had charged, the minister said.

Criminal proceedings would be halted “due to the lack of evidence of his involvement in the crime,” Kolokoltsev said, and Golunov would be released from house arrest Tuesday.

There was no immediate explanation for the rapid reversal, one that did not even involve the court system. Although the drug charges against Golunov were widely perceived as manufactured, that has not stopped the prosecution of numerous activists and journalists on the same grounds.

Golunov’s case unrolled in Moscow, however, with the public outcry expanding by the day. Supporters had called for a huge protest march on police headquarters Wednesday, Russia’s national holiday. Dmitri S. Peskov, the spokesman for Putin, had expressed concern that the march might overshadow the festivities.

There have also been reports that Putin wanted the case out of the way before June 20, when he is scheduled to hold his annual national call-in show, where people from around the country bring their questions and problems directly to the president.

Analysts had speculated that authorities would act quickly to defuse the situation, especially after many celebrities and other public figures who are normally supportive of the Kremlin made public statements demanding that Golunov be released. Even state television, which habitually ignores such cases, made Golunov’s release its top story Tuesday.

His employer, the Latvia-based Meduza news service, issued a statement welcoming the release.

“This is the result of an unprecedented international campaign of journalistic and civic solidarity,” Meduza said in a statement. “Together we all did the incredible: We stopped the criminal prosecution of an innocent person. Thank you!”