US-BACKED Syrian fighters have pushed on against members of Daesh in northern Syria under the cover of coalition air strikes and are closing in on a strategic town that is home to the country’s largest dam.

The latest advance by the Kurdish-led Syrian Democratic Forces (SDF) showed that operations were still ongoing after last week’s US missile attack on a Syrian army air base in the country’s centre.

The strike followed a chemical attack on the northern town of Khan Sheikhoun that killed 87 people. The US blamed the Syrian government for the attack – a charge that Syria strongly denied, saying it hit a rebel arsenal that had chemical weapons.

The British-based Syrian Observatory for Human Rights said the fighting between the SDF and Daesh on the eastern outskirts of the town of Tabqa left at least 11 extremists dead.

It said 36 Daesh fighters have been killed in the fighting since Sunday.

The SDF said on social media that its fighters marched about three kilometres from the eastern side of Tabqa, the location of Syria’s largest dam.

Last week, their fighters captured the area of Safsafeh, east of Tabqa, laying siege to the town. On March 22, US aircraft ferried forces behind militant lines in the Tabqa area to spearhead a major assault near the extremists’ de facto capital, Raqqa.

US Secretary of State Rex Tillerson, meanwhile, used a visit to a Second World War memorial in Italy to declare that the US will stand up to aggressors who harm civilians.

It came as the Trump administration sought to rally world leaders behind its strategy to resolve Syria’s protracted civil war.

Opening his visit to Italy, Tillerson travelled up a winding mountain road to Sant’Anna di Stazzema, the Tuscan village where the Nazis massacred more than 500 civilians.

As he laid a wreath at the site, he alluded to last week’s chemical attack in Syria.

“We rededicate ourselves to holding to account any and all who commit crimes against the innocents anywhere in the world,” he said.

“This place will serve as an inspiration to us all.”

Tillerson’s visit to Europe has been overshadowed from the start by US President Donald Trump’s decision to punish Syrian President Bashar al-Assad for using chemical weapons by launching cruise missiles at a Syrian air base.

The US military action has renewed the world’s focus on Assad’s fate and on Syria’s civil war, now in its seventh year.

Tillerson’s pledge to stand up for innocents came as Assad continued to attack civilians in Syria in the days since the US air strikes – including in the part of Idlib province where the chemical attack occurred.

And while other US air strikes in Syria have targeted Daesh, the US has acknowledged that civilian casualties sometimes occur.

Tillerson plans to use his meetings with foreign ministers from the G7 group of seven industrialised countries – normally a venue for economic discussions – to try to persuade leading countries to support the US plan.

The centrepiece of that diplomacy will come this morning when he takes part in a meeting of “like-minded” nations on Syria, including several Arab nations invited to attend.

He began to deliver that message yesterday when he met on the sidelines of the G7 with British Foreign Secretary Boris Johnson and French Foreign Minister Jean-Marc Ayrault.

Both countries have voiced support for the US response to Assad’s chemical weapons use.

Trump’s administration is hoping that after defeating Daesh in Syria, it can restore stability by securing local ceasefires between Assad’s government and opposition groups. This would allow local leaders who have fled to return and by restoring basic services.

The next step would be to use UN talks to negotiate a political transition that could include Assad leaving power.

From Italy, Tillerson will travel to Moscow, becoming the first Trump administration official to visit Russia. That trip, too, is fraught with tension over Syria.

Tillerson has accused Russia, Assad’s strongest ally, of either complicity or incompetence for allowing him to possess and use chemical weapons.

Meanwhile, the chair of the foreign affairs committee of Iran’s opposition in exile, the NCRI, has said Iranian President Hassan Rouhani had pledged his support for Assad in a phone call between the two.

Mohammad Mohaddessin said the call indicated that “first, the Iranian regime is fully participating in the crimes against humanity, war crimes and genocide that are perpetrated in Syria.

“Second, it proves that both factions of the clerical regime, which has acted as the main obstacle to the overthrow of Assad in the past six years, have total unanimity in supporting Assad and the massacre of the Syrian people.

“So far as it pertains to suppression and export of terrorism and extremism, there is no difference between the Iranian regime’s factions.”

Elsewhere, a judge in Spain has begun hearing evidence of potential war crimes allegedly committed by Assad’s regime in Syria.

The claimant, Amal Hag Hamdo Anfalis, is a Spanish national whose brother was allegedly abducted and tortured in the Syrian capital of Damascus, before being executed in 2013.

She told a National Court judge in Madrid yesterday that her brother was only a driver transporting nuts and dried fruits in his truck and had no involvement with the Syrian opposition.

Assad himself is not being investigated given his immunity under international laws, but nine of his close aids in the security and intelligence apparatus are, including long-time Vice President Farouk al-Sharaa and intelligence chief Ali Mamlouk.