Russian police have "stooped to a new low" by detaining "dozens of teenagers" during peaceful protests against the government's plan to raise the retirement age, Amnesty International says.

The London-based human rights watchdog made the statement on September 10, a day after more than 1,000 people were detained nationwide as anti-Kremlin demonstrators took to the streets in rallies coinciding with regional and local elections.

Footage of the rallies showed police officers sometimes using force to disperse gatherings, hitting demonstrators with batons and dragging them away.

Pictures of the police manhandling young people went viral on social media.

Fourteen journalists were also among those detained and another three were beaten up, according to the independent Trade Union of Journalists and Media Workers.

Kremlin spokesman Dmitry Peskov defended the police’s actions. He said the officers acted "in strict accordance with the law," adding that some of them were attacked by "hooligans and provocateurs."

Marie Struthers, Amnesty International’s director for Eastern Europe and Central Asia later said in a statement that police being sent to the streets in Russia to "crush" peaceful protests, beating demonstrators and journalists, was "nothing new."

"However, the police have stooped to a new low by treating young peaceful protesters as if they were criminals. This is shameless and heartbreaking," she added.

Struthers also said that young people in Russia were "increasingly being given the message that they should not expect their rights to liberty, freedom of expression, and peaceful assembly to be respected by the Russian authorities."

Hundreds Detained

Meanwhile, the European Union called on the Russian authorities to release "without delay the peaceful demonstrators and the journalists" who were detained.

The actions by the Russian police "prevented the exercise of the freedoms of expression, association, and peaceful assembly," EU foreign policy chief Federica Mogherini’s spokeswoman, Maja Kocijancic said in a statement, adding that the detention of journalists “undermines the freedom of expression."

The rallies against the pension-reform plan were announced last month by opposition politician Aleksei Navalny, who is currently serving a 30-day jail sentence for what authorities call violations of the law on public gatherings related to street rallies in January.

At least 1,018 demonstrators were detained at protests in 33 towns and cities, according to OVD-Info, an independent group that monitors the police response to protests.

OVD-Info said 183 were also held in the Urals city of Yekaterinburg, 60 in the southwestern city of Krasnodar, and 43 each in Moscow and the Siberian city of Omsk.

Some of the protesters detained are facing criminal charges.

Viktor Fedoseyev and Vasily Kostylev, who were detained in central Moscow in connection with the protests, have been charged with assaulting an officer, according to the Open Russia civic movement established by former Russian tycoon and Kremlin foe Mikhail Khodorkovsky.

Approval ratings for President Vladimir Putin, Prime Minister Dmitry Medvedev, and the ruling United Russia party have fallen noticeably since the proposed pension-age hike was passed in its first reading in the lower house of parliament in July.

The original plan would have increased the retirement age for men from the current 60 to 65, and from 55 to 63 for women. Putin later modified the proposal so women would retire at age 60.

According to various polls, about 90 percent of Russians oppose the plan to raise the retirement age, and a recent poll by the Levada Center polling agency found that more than 50 percent of Russians say they would participate in protests against it.

With reporting by Reuters, AFP, AP, TASS, Current Time TV, and Dozhd TV