ST. PETERSBURG, Russia — Before leaving for home after the Group of 20 summit, President Barack Obama sat down with Russian civil society activists on Friday evening to assure them that he would keep pressing Moscow to respect human rights, some of the activists said. But Obama also explained to them why this wasn't always possible.

"He was telling us how difficult it is for him to raise these issues, especially in relations with Russia and China," said Pavel Chikov, who heads Agors, a legal aid nongovernmental organization.

During the meeting that lasted an hour and a half, Obama spoke of his past as a community organizer and said he enjoys doing these events in each country he visits.