MOSCOW >> Russian President Putin on Friday signed a bill allowing authorities to issue electronic notices to draftees and reservists amid the fighting in Ukraine, sparking fears of a new wave of mobilization.

Russia’s military service rules previously required the in-person delivery of notices to conscripts and reservists who are called up for duty. Under the new law, the notices issued by local military conscription offices will continue to be sent by mail but they would be considered valid from the moment they are put on a state portal for electronic services.

In the past, many Russians avoided the draft by staying away from their address of record. The new law closes that loophole in an apparent effort to create a tool for quickly beefing up the military ahead of a widely anticipated Ukrainian counteroffensive in the coming weeks.

Recipients who fail to show up for service would be prohibited from leaving Russia, would have their drivers’ licenses suspended and would be barred from selling their apartments and other assets.

The bill signed into law by Putin was published on the official register of government documents.

Kremlin critics and rights activists denounced the legislation as a step toward a “digital prison camp” that gives unprecedented powers to the military conscription offices.

Lyudmila Narusova, the widow of former St. Petersburg mayor Anatoly Sobchak, was the only house member who spoke against the measure when the Federation Council, the upper house of parliament, considered the bill Wednesday.

Narusova, whose late husband was Putin’s mentor, charged that the bill contradicts the country’s constitution and various laws, and strongly objected to its hasty approval.

The swift enactment of the law fueled fears of the government initiating another wave of mobilization following the one that Putin ordered in the fall.

Russian authorities deny that another mobilization is being planned. Kremlin spokesman Dmitry Peskov said this week that the measure was needed to streamline the outdated call-up system in view of the flaws that were revealed by last fall’s partial mobilization.

“There was a lot of mess in military conscription offices,” he said. “The purpose of the bill is to clean up this mess and make the system modern, effective and convenient for citizens.”

Putin announced a call-up of 300,000 reservists in September after a Ukrainian counteroffensive that pushed Russian forces out of broad areas in the east.

The mobilization order prompted an exodus of Russian men that was estimated to number in the hundreds of thousands.

Observers say the new law appears to give authorities a mechanism for quickly beefing up the ranks in preparation for a new Ukrainian attack.

“A possible reason is that they see that the Ukrainians are getting ready for an offensive,” said Abbas Gallyamov, a former Putin speechwriter turned Kremlin critic who has left Russia.

Gallyamov has been labeled a “foreign agent” by the Russian authorities, a designation that implies additional government scrutiny and carries strong pejorative connotations aimed at undermining the recipient’s credibility. He also has been put on a wanted list for criminal suspects.

Gallyamov said the law could fuel smoldering discontent but would be unlikely to trigger protests.

“On the one hand, there is a growing discontent and reluctance to fight, but on the other hand there is a fear of escalating repressions,” he said. “People are put before a difficult choice between going to battle and dying, or landing in prison if they protest.”