Russian authorities arrested over 1,200 protesters Wednesday for opposing a “partial mobilization” of reserve military units by President Vladimir Putin, according to The New York Times.

The Russian General Prosecutor’s Office warned citizens Wednesday that protests could result in up to 15 years in prison, yet the mobilization announcement spurred “Send Putin to the trenches!” and “Let our children live!” chants across the country, the NYT reported. Following the announcement, Russian authorities charged protestors with intent to “disseminate false information” and “discredit the Russian Army,” actions that were made illegal in March, the NYT reported.

The arrests took place in 38 cities across Russia and followed the activation of 300,000 reservists, reported OVD-Info, a human rights watchdog that monitors police activity, according to the NYT. In response, Russian citizens formed a petition Wednesday with 300,000 signatures, the NYT reported.

One of the petition’s leaders, Anastasia, told the NYT, “I think people couldn’t pull themselves out of shock — they simply couldn’t believe that there would be a mobilization announced. Even yesterday we thought that it couldn’t happen.”

Dagestan in #Russia. Men don’t want to enlist. A fanatical woman tries to convince them.

– Why do we have to go to this war?
– Because it’s a war for our future!
– What future? We don’t even have the present!#mobilisation #StopPutin pic.twitter.com/s0UziyozJ9

— olexander scherba🇺🇦 (@olex_scherba) September 22, 2022

In Russia, a reservist is considered any man ages 18 to 27. Defense Minister Sergei K. Shoigu has said that the draft will only consist of prior military personnel, yet many Russians fear a broader draft is in the near future, the NYT reported.

Since the beginning of the war, as many as 25,000 Russian soldiers have been killed, the NYT reported.