The vandalism occurred on the day a new law took effect requiring Russian organizations receiving funding from other countries to register as foreign agents, RIA Novosti reported. Critics say the law, along with another one signed recently by President Vladimir Putin that widens the definition of treason, is part of a crackdown on dissidents pushing for legal reform and respect for human rights.
Memorial, one of the vandalized organizations, posted photographs on its Facebook page. Lev Ponomaryov, head of For Human Rights, said he found the spraypainting early Wednesday when he arrived at the organization's office.
Ponomaryov has refused to register as a foreign agent.
Young Guard, the ruling United Russia Party's youth group, demonstrated Wednesday outside the U.S. Russia Foundation, which funnels money to human rights non-governmental organizations. Demonstrators placed a large sign on the office labeling the foundation as a foreign agent.
Maxim Rudnev, one of Young Guard's leaders, defended the registration law via Twitter.
"Only NGOs in the political sphere fall under the law on 'foreign agents,'" he said. "NGOs in other spheres are not included."