Syrian rebels in northern Aleppo are, village by village, coming from the west, kicking Islamic State off the Turkish border and threatening to take the town of Dabiq, a place that has mystical symbolism for the extremist group.
Dabiq is the name of the group's English-language magazine and it is where the group's founder, Abu Musab al-Zarqawi, seemed to believe there would be a war of Armageddon. Losing it would be a blow to morale.
Strategically, depriving Islamic State - often referred to by rebels as Daesh, an Arabic acronym - of key real estate on the Turkish border will impede cross-border smuggling operations and leave it isolated in the so-called Manbij pocket.
With Kurdish forces on the east of the Manbij pocket and Syrian President Bashar al-Assad's troops moving slowly from the south, Islamic State has found itself almost surrounded and supply routes to its de-facto capital Raqqa under pressure of being strangled.
"The main aim of our current battle is to cut the routes for Daesh from Turkey," says Ahmed al-Ahmed, a spokesman for the Faylaq al-Sham Brigade, an Islamic faction that is one of the main groups fighting Islamic State in the area.
In particular, he says, the objective is to prevent new jihadists from Europe being able to smuggle themselves into Islamic State territory and join the battle.
Turkey stepped up efforts last year to control its frontier, but rebels admit that the recent capture of the border town al-Rai is significant because routes were still open.
"The battles are fierce. We are carrying out these battles to cut off Daesh from Turkey," says Mohammed Nour, a spokesman for the Sultan Murad Brigade, an Islamic alliance mostly based on ethnic Turkmen militias.
He says the US-led anti-Islamic State coalition, which primarily launches airstrikes against the extremist group, helped the fight.
Rebels spoke with dpa by phone and via a messaging application.
The rebels in northern Aleppo lost their front lines with al-Assad's forces in February, after they were cut off from Aleppo city due to intense Russian airstrikes backing the government.
Kurdish forces have since slipped in between government-held areas and the rebels. Shortly thereafter, Russia stopped its airstrikes, allowing the northern fighters to push east against Islamic State.
This appears to have suited US plans, as Washington was urging Turkey to focus its efforts and those of the factions it supports on Islamic State, rather than al-Assad.
Moreover, Ankara had been concerned by Kurdish advances from the east, which could have seen Manbij come under their control.
Increasingly, Turkey has stepped up its rhetoric against the Kurdish People's Protection Units (YPG) and also shelled its positions.
Ankara has long been concerned about nationalism among its large Kurdish minority and is facing armed conflict with rebels of the banned Kurdistan Workers' Party PKK in south-eastern Turkey.
The YPG has been the most effective fighting force so far in battling Islamic State, seizing vast stretches of territory from the extremist militia across northern and eastern Syria with the help of US airstrikes.
It appears that Turkey is keen now to see the rebels advance in Manbij and is hoping the US will hold back the YPG.
Idriss Nasan, a ranking Kurdish official in northern Syria, says he believes the next prize to be contested is Jarablous, the last major border town in Islamic State hands, located immediately to the west of YPG position, just across the Euphrates River.
"In my point of view, the race will be for Jarablous since it is on the Turkish border," he says, adding that Ankara will have no choice but to let the YPG control southern Manbij, because their forces cut Islamic State's supply routes.
He notes that US military officials and Kurdish leaders recently met in Kobane, in northern Syria.
"They discussed the plans and strategies of moving west of the Euphrates banks," he adds.
All this spells trouble for Islamic State. However, at the same time, experts are warning that al-Qaeda's wing in Syria is gaining strength, with risks that the threat is being ignored.
Al-Nusra Front – which along with al-Qaeda's branch in Yemen is among the best at adapting to local environments - seems more intent on establishing itself as a ruling power.
The Syrian wing increasingly fights more moderate rebels and is holding significant territory in Idlib province.
Even if Islamic State is eventually degraded, there is still al-Qaeda, the original enemy of the US in the Long War on terrorism, now in its 15th year.