U.S. President Barack Obama and Russian President Vladimir Putin on Monday agreed that they disagree about the situation in Syria.

At the same time, reported the AFP news agency, the two leaders pledged to at least try to keep alive a frail and much-delayed effort to hold a Geneva peace conference.

The U.S. and Russian presidents faced off on the sidelines of the G8 summit in Northern Ireland, days after the White House signaled it would begin arming rebels battling Syrian President Bashar Al-Assad.

Putin and Obama did not try to disguise the fact they are estranged on Syria and cannot agree on Assad’s fate — but appeared keen to keep flagrant differences on the vicious civil war from sinking wider U.S.-Russia relations.

They announced Obama would go to Moscow on September 3-4 for a full-scale summit, expanding a previously announced trip that includes the G20 summit in St. Petersburg, according to AFP.

They spoke of cooperation on terrorism and economics, with Russia now in the World Trade Organization, and agreed to revive a frozen agreement which secures loose nuclear and radioactive materials in the former Soviet Union.

On Syria, however, the differences remain deep.

“Of course our opinions do not converge, but all of us have the intention to stop the violence in Syria and stop the growth in the number of victims,” said Putin, who has scoffed at U.S. plans to begin arming selected rebels.

He said he and Obama agreed that the vicious civil war that has killed at least 90,000 people must end “peacefully” and through talks.

“We agreed to push the parties to the negotiating table,” he said, according to AFP.

Obama acknowledged that they had “different perspectives” on Syria.

Washington and Moscow have agreed in principle to host a conference in Geneva on ending the violence in Syria, but the timetable for the meeting has continually slipped over disagreements on who should attend.

Still, Obama said he and Putin would instruct their teams to keep at it.

“We share an interest in reducing the violence, securing chemical weapons and ensuring that they are neither used nor are they subject to proliferation,” Obama said, according to AFP.

“We want to try to resolve the issue through political means if possible, so we will instruct our teams to continue to work on the potential of a Geneva follow-up.”

The U.S. government announced last week that the Syrian army used chemical weapons against rebel forces on multiple occasions, adding that America will increase the “scope and scale” of its assistance to rebels in Syria in response.

An aide to Putin said on Friday that Russia is not convinced by the evidence which the U.S. provided alleging that the Assad government used chemical weapons against rebel forces.

Putin himself on Sunday said that the Syrian rebels are “cannibals” and should not be given arms, referring to video footage posted on the Internet last month of a rebel fighter eating the heart of a government soldier.

Both leaders said they hoped Iran’s election would unfreeze the currently stalled talks between Tehran and world powers over the Islamic Republic’s nuclear program.

Obama said he and Putin had expressed “cautious optimism” that the election of the next Iranian president Hassan Rowhani, who is seen as a comparative moderate, could change the dynamics of the effort.

Putin said he hoped that the vote would reveal “new opportunities to solve the Iranian nuclear problem.”