As the conflict in Syria rages on, the US-Russia tensions are increasing in the country as well as lines of communications are not being used and the politics over Iran play an ever more important role.

The most recent war of words began when a US Navy fighter jet shot down a Syrian war plane without communicating with Russian forces about it ahead of time per normal procedure.

Russia, which has been an ally of Syrian President Bashar al-Assad, responded by saying that any US war planes in the vicinity of the incident would be treated as “targets”.

As Joshua Landis, Director of the Center for Middle East Studies at the University of Oklahoma, told The Independent the Syrian war plane was likely done bombing and the US "had to make a snap decision".

The Russian Defence Ministry called it "a cynical violation of the sovereignty of the Syrian Arab Republic". They have also said the US is blatantly violating international law "under the guise of ‘combating terrorism’."

The White House responded through Press Secretary Sean Spicer: “The escalation of hostilities among the many factions that are operating in this region doesn’t help anybody. And the Syrian regime and others in the regime need to understand that we will retain the right of self-defence, of coalition forces aligned against ISIS".

US Central Command (Centcom) confirmed that the US has shot down a pro-Syrian regime drone on Tuesday. It is the second such drone that has been shot down by the US in the last month.

Centcom said the drone was "display[ing] hostile intent" and was within firing distance of US troops. The Russian Defence Ministry has not yet responded to the drone being shot down.

Tensions had been mounting for some time now, however.

Russia has consistently vetoed any resolutions against the Syrian regime by the United Nations Security Council.

Ahead of the most recent veto in April 2017, the Russian UN representative Vladimir Safronkov said that Donald Trump's "aggression" in Syria is actually strengthening terrorist groups like Isis.

The comment came just hours after the US dropped nearly 60 missiles in the Idlib province of Syria after an apparent chemical attack in the area that killed approximately 100 people.

Graphic video footage of the aftermath showed several children were among the dead and injured.

After the missile attack, Russia made its first threat to sever the communications channel their and US troops had been using.

“Despite the harsh rhetoric then, the Russians kept the line open. Frankly, that’s because this channel is in the best interests of both sides, and the Russians should know that,” Eric Robinson, Research Programmer & Analyst at RAND Corporation told The Independent.

The channel helps organise a crowded airspace and “it’s critically important for protecting troops on the ground from an inadvertent airstrike targeted at other forces,” explained Mr Robinson.

He said though that Russia’s stance after the recent jet incident has been more “bellicose” than in the past.

In pictures: US missile strike against Syria Show all 7 1 /7 In pictures: US missile strike against Syria In pictures: US missile strike against Syria The guided-missile destroyer USS Porter (DDG 78) launches a tomahawk land attack missile in the Mediterranean Sea AP In pictures: US missile strike against Syria The United States military launched at least 50 tomahawk cruise missiles at al-Shayrat military airfield near Homs, Syria, in response to the Syrian military's alleged use of chemical weapons in an airstrike in a rebel held area in Idlib province EPA In pictures: US missile strike against Syria Shayrat airfield in Syria Getty Images In pictures: US missile strike against Syria US Navy guided-missile destroyer USS Ross (DDG 71) fires a tomahawk land attack missile in Mediterranean Sea Reuters In pictures: US missile strike against Syria US Navy guided-missile destroyer USS Ross (DDG 71) fires a tomahawk land attack missile in Mediterranean Sea Reuters In pictures: US missile strike against Syria President Donald Trump speaks at Mar-a-Lago in Palm Beach, Fla., after the US fired a barrage of cruise missiles into Syria in retaliation for this week's gruesome chemical weapons attack against civilians AP In pictures: US missile strike against Syria Syria's President Bashar al-Assad Reuters

Mr Robinson’s view is that once again threatening to close down the communication channel is a “bartering tool”.

Russia hopes to get a concession from the US or paint the picture that the US is unwilling to cooperate in defeating the Isis terror group.

The concession they may be hoping for could be regarding a bill imposing more expanded sanctions on Russia, including their economically crucial energy projects.

The bill passed the Senate with an overwhelming majority and is currently sitting in the House. The new Russia sanctions was actually tacked on as an amendment to an existing bill on Iran sanctions, a bit of political manoeuvring to handcuff both Republicans and Democrats to voting for it.

Mr Trump has repeatedly made eradicating Isis and other terror groups a main priority of his campaign and administration.

He has even criticised allies in the North Atlantic Treaty Organisation (Nato), the UN, and Middle Eastern countries for not doing enough to counter violent extremism.

As a result, a new counterterrorism centre was set up in Saudi Arabia during Mr Trump’s Riyadh visit.

Saudi Arabia and neighbours even cut diplomatic ties with Qatar over the small Gulf kingdom’s supposed financing of terrorism, though it is not clear the two events are related.

Russian pressure on that front could push the US to ask that the communication line remain open or concede on another issue in order to save Mr Trump’s falling job approval ratings and maintain his “America First” message.

Mr Robinson that the latest rhetoric is a clear indication that “all the major players of the Syrian conflict are beginning to converge on the same piece of territory”.

"As Isis collapses and retreats, new borders have to be hammered out" regarding which parts of Syria will be taken by the US and US-backed Kurds versus the al-Assad regime backed by Russia and Iran, said Mr Landis.

Mr Assad’s regime and Russia have consolidated control in Aleppo, so now attention is turned south and east as "Russia and Syria are probing into the edges of US territory," he explained.

It is no coincidence that the region in question is where most of Syria’s oil production happens. Though the fields are currently in Isis control, but once they lose the territory it will be a free-for-all according to Mr Robinson.

Mr Landis said a similar situation happened in the north in Jarablus and in Tanf in the south, where the US has 150 special forces and the US attacked what it called Iranian-backed Syrian troops.

Syria is worried the US will use a "proxy army" to caputre more and more territory in the south, which Syria and Iran consider under the rightful control of Mr al Assad.

In any case, “Russian, Iranian, American, and Syrian opposition forces will continue operating closer and closer to each other from here on out, with the potential for major flashpoints likely to increase”.

Iran adds another element to the conflict, which at this point appears to be in terms of "short-term military needs; self-defence," said Mr Landis.

Trita Parsi, president of the National Iranian American Council and author of Losing an Enemy: Obama, Iran, and the Triumph of Diplomacy, told The Independent: “we’re in a very dangerous moment”.

He thinks that the escalation of tensions between Russia and the US is “not accidental”.

He points to “some of the aggressive elements of the White House” who want a confrontation with Iran. However Mr Landis said he does not expect a full on war between any of the parties. The recent back and forth is more "teeth gnashing and growling".

Iran's Revolutionary Guard said it launched its own air strikes against Isis on 18 June, in response to terror attacks on the parliament building and a shrine in Tehran earlier this month.

Iran said surface-to-surface medium range missiles hit the Deir Ezzor province, where Isis militants fleeing advancing troops in Raqqa are hunkering down.

According to a statement, the missiles were launched from Iran's Kurdistan and Kermanshah provinces, over Iraq, on to their targets in Syria.

It has been confirmed how many Isis members were killed or if weapons stashes were affected by the Iranian missiles.

The statement also warned Isis militants and “regional and international supporters” against any more attacks on Iran.

Mr Parsi said that with coalition forces, Russia, and Iran honing in on the same territory will “at a minimum put the US and Iran in direct confrontation”.

He also said the recent increase in tensions can be linked to Mr Trump’s visit to Saudi Arabia, who is at odds with Iran over a number of issues - the latest of which is Qatar’s support of Tehran.

However, Mr Landis said that he does not think "anyone in Washington is going to be stupid" about what he refers to as the "new security architecture" in the northern Middle East where Iran has a strong influence.