ST. PETERSBURG, Russia — President Barack Obama says he had a "candid and constructive conversation" with Russian President Vladimir Putin on Syria.

Obama says that he urged Putin to set aside his differences with the U.S. over the use of chemical weapons and try to help encourage a political transition in Syria.

Putin told reporters they spoke for 20 or 30 minutes Friday and focused on Syria. The Russian president says while they disagreed, the meeting was constructive.

Obama says the humanitarian situation in Syria and along its borders is "only getting worse" and stresses that the problem is "not in anyone's interest."

Obama insists that the Syrian government is responsible for chemical weapons attacks against civilians and is pushing for the United States to respond with a military strike.