Moscow — The United States and Russia agreed Friday to take steps that could reduce the violence in Syria, but Secretary of State John F. Kerry and Russian Foreign Minister Sergei Lavrov said they will not outline what they are to prevent "spoilers" from disrupting the initiative.

In a late night news conference following talks that began in the morning and stretched until almost midnight, Kerry and Lavrov said they had agreed to do things that could cut down on civilian casualties and target designated terrorist groups.

Kerry combined a plea for urgency with a vagueness about what is being considered, or already agreed on.

"International efforts have failed the Syrian people for too long," he said. "After five years of war, the people of Syria don't want words, They want action, and they want to be able to live in peace."

Kerry said that while he and Lavrov had focused on steps to try to realize those goals, "We agreed the best way to make it real is to go about quiet business."

If the unspecified steps were "implemented in good faith," Kerry said, "It is possible to help restore the cessation of hostilities, significantly reduce the violence and help create the space for a genuine and credible political transition."

But, Kerry and Lavrov declined to spell out any concrete steps they had agreed on in what Kerry termed a "public, long list." He said more details need to be ironed out.

"I am here with confidence that if the things we talked about are implemented, this has a chance to change the situation," Kerry said.

"Let the proof be in the pudding."

The word "coordination" was never mentioned in their remarks to reporters, even though Kerry came to Moscow with a detailed proposal for the United States and Russia to share military intelligence in Syria and "synchronize" military operations to fight jihadists. A draft of the proposal said that Washington wanted Moscow in return to ensure the Syrian air force would be grounded and would no longer drop bombs on civilians under the guise of targeting terrorists.

Russia is one of the chief backers of Syrian President Bashar al-Assad, and its military support has allowed Assad, once on the ropes, to solidify his position. He said in an interview with NBC News last week that neither Putin nor Lavrov have ever suggested a transitional government that would force him from office, a position the United States continues to maintain.

That policy has not changed, Kerry said, allowing that, "We have a difference with Russia about that. But notwithstanding that difference, we both believe it is important for us to reestablish the cessation of hostilities."

A cease-fire in place since February has been marked by repeated violations, blamed by the State Department on Syrian forces and, to a lesser degree, on Jabhat al-Nusra, an al-Qaeda affiliate. By ending the violence, Kerry believes, the cease-fire can create conditions in which U.N.-brokered negotiations can occur.

Though Lavrov mentioned "joint efforts" almost in passing, Kerry said nothing being considered will change anything quickly.

"The results will not be tomorrow or the next day," he said. "It will not be immediate. But our patience is not limitless."

Kerry and Lavrov emerged from their talks 10 hours later than scheduled. Their discussions were interrupted only by a break of about four hours while Kerry went to the U.S. Embassy and consulted with Washington, including with officials at the White House and the Pentagon.

His meetings with Lavrov followed a three-hour meeting Thursday night with President Vladimir Putin. But the truck attack on Bastille Day revelers in the French city of Nice occurred while Kerry was still huddled with Putin, and the magnitude of the assault was unclear.

The casualty count was still rising when Kerry and Lavrov sat down Friday, and the attack bracketed their discussions.

Before the talks got underway, the two diplomats and their senior aides stood for a brief moment of silence in memory of the victims. Before they parted in the late afternoon for Kerry to go to the embassy, they rode together to the French Embassy in Moscow to lay wreathes and write in a condolence book.

"May we all show strength and purpose to end this scourge of terror and find peace in our time!"Kerry wrote.

Kerry and Lavrov said the violence in Nice underscored the need to combat international terrorism and end the violence in Syria.

"I believe that the dialogue is becoming even more urgent and relevant because of the barbaric and horrible terrorist attack that took place yesterday in Nice," said Lavrov.

Kerry looked grim and expressed weariness at how often he and other diplomats meet in the wake of terrorist attacks, many of them by extremists from or inspired by the Islamic State and its caliphate in Syria and Iraq.

"The problem," Kerry told Lavrov, "is you and I and other foreign ministers and leaders of countries are doing this now on almost a weekly basis. And nowhere is there a greater hotbed or incubator for these terrorists than in Syria."

Kerry told Lavrov cooperation in Syria could pave the way for Moscow and Washington to improve their bilateral relationship, which has been severely strained over Russia's support for separatists in Ukraine and its annexation of Crimea.

"I think people all over the world are looking to us, and waiting for us to find a faster, more tangible way of them feeling that everything possible is being done to end this terrorist scourge, and to unite the world in the most comprehensive efforts possible to fight back against their nihilistic, depraved approach to life, and death," Kerry added.

"And you and I and our teams are in the enviable position of actually being able to do something about it."