Washington: Frustrated by months of failure in Syria, the Obama administration is taking what might be its final offer to Moscow: Enhanced intelligence and military cooperation against Daeshand other extremist groups if Syria’s Russian-backed president Bashar Al Assad upholds a ceasefire with US-supported rebel groups and starts a political transition.

When Secretary of State John Kerry meets Russia’s top diplomat and possibly President Vladimir Putin in Moscow later this week, Syria’s civil war and Al Assad’s future will top the agenda. Kerry is trying to reverse a trend in which he has hailed a series of agreements with the Russians only for them to fall short, according to officials with knowledge of internal American deliberations.

Kerry will have to thread a needle. He’s watched the Syrian military and Russian air force violate truce after truce in recent months. This time, the officials said, Kerry is dangling in front of the Kremlin Russia’s long-sought requests for intelligence sharing and targeting assistance in return for Russia using its influence to end the fighting and start ushering Al Assad out of power. But Kerry will be wary about offering too much.

The talks in Moscow are scheduled fewer than three weeks before an August ultimatum for diplomatic progress. All signs augur poorly for a breakthrough. Fighting is intensifying near Aleppo, Syria’s largest city. Al Assad has reasserted control over more areas of the country he had once lost. Humanitarian aid deliveries to besieged, rebel-held areas are sporadic and grossly insufficient. And counterterrorism campaigns against Daeshand Al Qaida show no end in sight, meaning any peace would only be partial.

“The target date for the transition is 1st of August,” Kerry told reporters two months ago, hoping to get Russia and Syria to halt military operations. “So either something happens in these next few months or they are asking for a very different track.”

But that “very different track” has remained undefined beyond vague hints of a military intervention involving Saudi troops. The White House and Pentagon have resisted a greater US role.

As a result, Washington is stuck with a familiar strategy: Asking Russia to force Al Assad to halt military offensives against moderate rebels, stop bombing civilian areas and allow aid to reach besieged communities.

But as added carrots, the US is now offering more robust military cooperation against Daesh and the Nusra Front, Syria’s Al Qaida branch, and information to help Russia target affiliated militants. Kerry won’t go as far as to suggest joint US-Russian operations, according to the American officials, who weren’t authorised to speak on the matter and demanded anonymity.

“We have teed up ideas to the Russians,” State Department spokesman John Kirby told reporters Tuesday, saying the Moscow discussions would be an indicator of Russia’s sincerity.

In Azerbaijan, Russian Foreign Minister Sergey Lavrov blamed the UN’s Syria envoy for the diplomatic impasse, and said he would try to work with Kerry on a common approach after the top US diplomat’s arrival Thursday.

Much of Washington is wary about working too closely with Russia. The US doesn’t want to be seen as entrenching Al Assad, whom American officials have referred to as a “butcher” and “mass murderer.” Russia’s bombers also have attacked anti-Al Assad rebel groups that have received weapons, training and other forms of support from the US and allies such as Saudi Arabia - whose foreign minister Kerry met in Washington on Tuesday before a weeklong Europe trip.

And, as a dissent cable signed by 51 State Department officials illustrated last month, a sizeable part of America’s diplomatic establishment believe a US military response is necessary to resolve the Syrian conflict, given Moscow’s increased leverage through its presence on the ground.

When Russia intervened in Syria last September, the administration took a different view, branding it a move of desperation and weakness. The US initially sought to shut Russia out of diplomatic discussions, but quickly reversed course and created the International Syria Support Group with Moscow’s help. American officials including Kerry then softened demands for Al Assad’s prompt departure from power.

A cessation of hostilities was reached in February. Several temporary and regional truces have followed, though none have ended the violence that has killed as many as a half-million people since 2011, contributed to a global migration crisis and spawned Daesh’ international expansion.

On Tuesday evening, Kerry announced that the US will provide another $439 million in humanitarian aid to refugees and others affected by the ongoing conflict in Syria, bringing to $5.6 billion the total amount of American aid given since the start of the crisis in 2012.

While some US officials downplay the military significance of what is now being offered to Russia, the symbolic effect is clear. Russia has been keen to present its intervention as part of the global effort against Daesh and other extremist groups, and not as a ploy to keep Al Assad in power. More cooperation with the US could reinforce that narrative. The arrangement also could give Moscow greater cover to expand operations against forces the US considers moderate.

The Pentagon is concerned about such a scenario, according to the officials. But the administration has few options right now, given the various, unfulfilled threats throughout Syria’s civil war to apply greater US force - from declaring Al Assad’s days “numbered” five years ago to Obama’s vow of a military response if chemical weapons were used and then backing down in 2013.