Russia's lower house of parliament on Tuesday quickly rubber stamped a new bill widely expanding the definition of high treason. Critics alleged the legislation is part of a wider crackdown on dissent by President Vladimir Putin, who has already pushed through laws targeting street protests, aid organizations and opposition leaders.

Current law describes high treason as espionage or other assistance to a foreign state damaging Russia's external security. The new bill expands it to include moves against Russia's "constitutional order, sovereignty and territorial and state integrity."

The bill, drafted by the Federal Security Service, the main KGB successor agency, also changes the interpretation of treason to include activities such as financial or consultative assistance to a foreign state or an international organization.

The bill, which the lower house, the State Duma, overwhelmingly approved Tuesday, is certain to quickly sail through the equally pliant upper house before Putin signs it into law. It keeps the punishment of up to 20 years in prison used by the current law.

Rights activists have warned that the new bill is so loosely worded that it would allow the government to brand any dissenter a traitor.

"It would allow them to put any civil activist, let alone rights defender, in custody," said Lev Ponomaryov, a veteran Russian rights activist. "It will place a sword over the head of anyone who is maintaining contacts with foreigners."

The socialist Just Russia party was the only Duma faction that didn't vote for the bill, although it stopped short of voting against it. Just Russia leader Sergei Mironov voiced concern that the bill's loose wording could allow the authorities to use it to stifle dissent.

Russia's rights ombudsman, Vladimir Lukin, also criticized the bill, saying it would free investigators of the need to prove that a suspect inflicted any actual damage to the nation's security.

Putin has clamped down on the opposition following a series of major street rallies against his re-election to a third term as president in March. The Russian leader has claimed that the protests were staged by Washington in order to weaken Russia, and he filled his campaign with anti-American rhetoric.

New repressive laws have been passed to deter people from joining protests, and opposition activists have been subject to searches and interrogations.

One of the laws passed this summer obliged non-governmental organizations that receive foreign funding and engage in vaguely defined political activity to register as "foreign agents," which is intended to destroy their credibility among Russians.

Earlier this month, Moscow declared an end to the U.S. Agency for International Development's two decades of work in Russia, saying that the agency was using its money to influence elections — a claim the U.S. denied.

In August, a court handed down two-year prison sentences to three members of the punk band Pussy Riot for performing an anti-Putin song inside Moscow's main cathedral. One was freed earlier this month after a court suspended her sentence, but the other two were sent from a Moscow jail to remote prison colonies this week.

In the latest attack on the opposition, Russian investigators have accused several activists of plotting riots based on hidden camera footage of their alleged meeting with a Georgian lawmaker that was aired earlier this month by a Kremlin-friendly TV station.

Authorities formally charged one of the activists, Leonid Razvozzhayev, Tuesday, marking the start of a criminal probe against him. He alleges he was kidnapped from Ukraine where he was seeking asylum, returned to Russia and tortured into confessing to organizing riots. Officials denied his claim, saying he turned himself in.

Ponomaryov, the veteran rights activist, described the latest events in Russia as part of an increasing isolationist streak in the Kremlin's policy.

"The country's rollback to the past is accelerating," he said.