Intervention by external powers against Syrian government forces is likely to increase as the campaign against the Islamic State terror group winds down and Damascus eliminates remaining insurgent-held enclaves.
Last weekend missiles apparently fired by Israeli war planes struck an arms depot near Homs, killing 26, reportedly Iranians and members of an Iraqi militia. This attack coincided with the bombing by US aircraft of a column of pro-government forces deployed to reinforce comrades who had captured villages in an area east of the Euphrates river held by US-backed Kurdish Syrian Democratic Forces (SDF) militiamen.
Israel has been coy about its involvement in the strikes near Homs but, fearing retaliation, closed its airspace near the sensitive Syrian border. The SDF announced US aircraft had "inflicted heavy losses" on advancing loyalist fighters. Nine were reportedly killed.
US air strikes in February on pro-government forces nearing another SDF base east of the Euphrates killed up to 200, including Russian military contractors.
The latest Israeli and US operations took place during Syrian army offensives against the last southern suburbs of Damascus under jihadi control and an insurgent held-pocket centred on the town of Rastan, between Homs and Hama. After surrounding these areas under cover of heavy bombardment, the Syrian army proposed ceasefires which would allow armed elements to evacuate or surrender in exchange for amnesty.
Divided
While fighters in the Rastan enclave have not yet decided, jihadis in the capital's suburbs are divided. Al-Qaeda-affiliate Hay'at Tahrir al-Sham has accepted but Islamic State, also known as Isis, has rejected the deal, prompting the Syrian air force to strike the area it holds while buses lined up to carry Hay'at Tahrir fighters north to jihadi-held Idlib province.
Islamic State continues to occupy sectors of the suburbs of Yarmouk, Hajjar al-Aswad and Qadam, where the group gained a foothold in 2012. The UN agency that looks after Palestinian refugees, Unrwa, has expressed concern for civilians remaining in Yarmouk, the former site of the largest Palestinian refugee camp outside Palestine.
The agency reported 5,000 Palestinians had fled Yarmouk to government-held areas and called for safe passage for trapped civilians.
As Tahrir al-Sham fighters fed hostages and departed, 1,500 civilians from the jihadi-besieged loyalist Shia towns of Fouaa and Kefraya boarded buses for Aleppo in the first stage of an evacuation of 5,000 set to be completed by May 15th, before the beginning of the Muslim fasting month of Ramadan.
Syrian quagmire
Although the US dismantled the command structure overseeing the fight against Islamic State in Iraq, Washington appears to be increasingly drawn into the Syrian quagmire, risking conflict with Russia and Iran, the chief external actors backing the government. Ahead of the the April 14th US-led tripartite missile strikes on alleged Syrian chemical weapons sites, Moscow warned Washington it would respond to attacks killing Russian troops and airmen.
Russia has also made clear it is prepared to defend its presence in Syria where over the past seven years it has invested considerable resources and the lives of military personnel to support the government.
Chief regional assets
As the US and Israel step up their campaign against Iran, Tehran is likely to strengthen its commitments to Damascus, Lebanon's Hizbullah movement, and Iraqi Shia militias, the Islamic' republic's chief regional assets. President Bashar al-Assad remains in power in Damascus while Hizbullah and Iraqi Shia militias stand to gain seats in their countries' coming parliamentary elections.
US revocation of the 2015 agreement for dismantling Iran’s nuclear programme in exchange for lifting sanctions could provoke violent clashes between US and pro-Iranian forces in Iraq and Syria, risking regional warfare that could involve Israel and deepen divisions in the already divided Arab world.