A US soldier was killed Thursday as dozens of US Delta Force commandos raided an Islamic State base in northern Iraq. The raid marked the first publicly acknowledged instance of direct ground combat by US forces in Iraq since the official end of US combat operations in 2011.

The US special forces troops were embedded with a unit of Kurdish “Cobra” fighters, as part of a mission supposedly aimed at rescuing some 70 prisoners, said to be facing execution at the hands of Islamic State militants.

The incident has become the center of US media frenzy in recent days, focused on the death of Master Sergeant Joshua Wheeler, who was killed in combat during the operation. Wheeler, a veteran of 14 deployments to US war theaters in the Middle East and Central Asia, is reportedly the first officially acknowledged US casualty in Iraq since 2011.

The US raid, the true purpose of which remains unclear, was authorized by the top US defense official, Defense Secretary Ashton Carter. While upholding the pretense that US troops are present merely as “advisors,” Carter acknowledged that US forces played a combat role in the mission.

“This is combat, things get complicated,” Carter said.

Despite the supposed “end” of the Iraq war, at least 3,300 US troops are currently stationed inside Iraq, as part of the renewed US military intervention launched in June 2014. The US military is preparing to further increase its overall troop presence and expand its network of permanent US military bases inside Iraq, as part of a general escalation of its regional operations.

“It is important to realize that U.S. military support to this Iraqi rescue operation is part of our overarching counter-terrorism efforts throughout the region,” said US General Sean MacFarland, the top officer for the post-2011 phase of the US war in Iraq, codenamed Operation Inherent Resolve.

The US-Kurdish mission was launched further south than Kurdish forces typically operate, and Iraqi authorities were not notified in advance by the US military, producing consternation in Baghdad, an anonymous Iraqi Defense Ministry official told the Washington Post .

Washington's military alliance with various Kurdish forces is fueling increased tensions with Baghdad. The Iraqi government fears that Washington will back the Kurdish Regional Government's (MRG) ambitions for greater control over northern Iraq's substantial oil reserves, and even full recognition as an independent state, in exchange for Kurdish collaboration with US operations in both Iraq and Syria.

In comments Friday, Iraqi parliamentarian and defense committee chair Hakim al-Zamili described Thursday's raid as a “dangerous thing” that had set off alarm bells in Baghdad.

The growing conflict between the US and its erstwhile puppet government in Baghdad is being amplified by stepped up Russian military and intelligence activities on both sides of the Iraq-Syria border.

“The United States has been worried by the growing influence of Iran in Iraq and worries should be doubled after the Russians took the lead in Iraq and Syria,” a former Iraqi general told Reuters.

While the bulk of Russian forces have thus far been allocated to the war in Syria, Moscow is already working closely with the militaries of Syria, Iraq and Iran through a joint planning and intelligence cell in Baghdad. Iraqi politicians have recently expressed hopes that the Russian-led planning cell may emerge as the hub for a substantial Russian military campaign within Iraq, similar to that being waged by Moscow in Syria.

US officials have warned that Russian military operations in Iraq would force Washington to rethink its own military support for the Baghdad government of Iraqi Prime Minister Haydar al-Abadi.

“It would make it very difficult for us to be able able to provide the kind of support that you need if the Russians were here conducting operations as well. We can't conduct operations if the Russians are operating in Iraq right now,” US General Jospeh Dunford told media during a visit to Iraq this week.

Abadi represents sections of the Iraqi elite which retain a relative pro-US orientation and are fearful of overly strong Iranian influence in Baghdad. Nonetheless, the Iraqi prime minister is coming under “tremendous pressure” from Iraq's national bourgeois elite to authorize a full-blown Russian military campaign against Sunni militants in Iraq, according to Iraqi MPs cited by Reuters.

A growing chorus within Iraq's Shi'a-dominated political elite have denounced Washington for its failure to follow through on promises of an aggressive campaign to destroy ISIS. Iraqi leaders have complained that US operations in Iraq are tailored to contain ISIS, rather than to actually defeat and dismantle the militant group.

The Russian air campaign in Syria, which has succeeded in driving back US-backed Sunni militants in the central Syrian provinces of Latakia and Homs since its launch in early October, has spurred calls from Iraqi leaders to embrace a similar Russian role for Iraq.

Baghdad would welcome Russian efforts to “complement the fight we have against ISIS,” Iraqi ambassador to the US, Lukman Faily, said in recent comments to CNN.

“Russia, other countries, have their own threat in relation to ISIS, and they also have a stake. We would like, and seek support from, all who can help to cleanse our country from ISIS,” Faily said.

“In the upcoming few days or weeks, I think Iraq will be forced to ask Russia to launch air strikes, and that depends on their success in Syria,” top Shi'ite political leader Hakim al-Zamili told Reuters in early October.

“We are seeking to see Russia have a bigger role in Iraq,” Zamili said. “Yes, definitely a bigger role than the Americans.”

“We are losing billions of dollars in oil revenues by purchasing arms from the United States, but what we really got from them was only promises and dozens of delayed arms deals,” the leading Iraqi politician said.

Iranian-backed Shi'ia militias operating in Iraq have called even more openly for Russia to supplant the US as the main outside power in the country. “The Russian intervention came at the right time and right place and we think it will change all rules of the game not only in Syria but in Iraq also. This government has been relying on an untrustworthy ally, which is the United States, and this fault should be fixed,” a leading Shi'a militant told Reuters.

Though motivated by the sectarian interests of Iraq's Shi'a establishment, accusations that Washington has soft-pedaled its anti-ISIS effort are basically well founded. Despite the constant demonization of ISIS in the US media, Washington's military-political grip over Iraq increasingly depends on an array of Sunni militant groups, including militant factions closely affiliated with ISIS.

In an apparent effort to demonstrate its readiness to wage sustained attacks against US-aligned Sunni forces in Iraq, on Thursday Russian planes bombed a key bridge spanning the Euphrates river, along the Syrian-Iraq border Thursday, near the city of Deir ez-Zor.

Given its location, the Russian attack was likely intended to hamper the flow of Sunni militants from Syria into Iraq. For at least a decade, the Sunni insurgency in Iraq has relied on reinforcements flowing into Iraq from Syria. The precursor organization to ISIS, Al Qaeda in Iraq (AQI), relied on precisely this corridor to replenish its ranks during the insurgency against the US occupation, smuggling fighters from Syria into central and western Iraq.

The targeting of a central node of the Euphrates corridor by Russia is a further sign that Moscow is jockeying to displace the US as Baghdad's main foreign patron.

Under these circumstances, the turn by the US to a new round of ground combat operations in Iraq underscores the explosive dynamics being engendered across the Middle East by mutually intensifying regional and global struggles.