American-led forces and their Syrian Kurdish allies carried out their biggest joint operation against ISIS in Syria since President Donald Trump ordered a pullback of US forces there. The US-led coalition said on Saturday that hundreds of US-allied Syrian Kurdish forces took part in Friday's action. Coalition officials say the operation captured dozens of militants. The news came on the same day Vice President Mike Pence visited Iraq and worked to reassure America's Kurdish allies in the region. The Trump-ordered pullback of American forces in Syria opened the door for a cross-border offensive by Turkey last month, leaving Syrian Kurds to face a bloody Turkish assault. Mr Pence said the US commitment to both Syrian and Iraqi Kurds remains unchanged. Flying in a C-17 military cargo aircraft, Mr Pence landed in Irbil, capital of Iraq's semiautonomous Kurdish region, to meet with Iraqi Kurdistan President Nechirvan Barzani. The visit was meant to hearten the United States' regional partners in the fight against the Islamic State group after the US pulled troops from northern Syria, leaving America's Kurdish allies there to face a bloody cross-border Turkish assault last month. Asked by reporters if the United States was facing a sense of betrayal from Iraqi and Syrian Kurdish allies over Trump's actions in Syria, Pence said both groups, including Syrian Kurdish forces "who fought alongside us," had no doubts about the US commitment to them. "It's unchanging," Mr Pence said. Earlier, Pence received a classified briefing at Iraq's Al-Asad Air Base, from which US forces are believed to have launched the operation in Syria last month that resulted in the death of Islamic State leader Abu Bakr Al Baghdadi. Mr Pence also spoke by phone with Iraqi Prime Minister Adel Abdul-Mahdi. Underscoring Mr Pence's message that American military partnership with Syrian Kurdish forces is ongoing, the US-led coalition said on Saturday that its forces, along with hundreds of Syrian Kurdish commandos, had jointly carried out the largest operation against ISIS in eastern Syria since the US pullback began in early October. Mr Pence's trip on Saturday was his second to the region in five weeks. Mr Trump deployed him on a whirlwind journey to Ankara, Turkey, last month to negotiate a cease-fire after President Recep Tayyip Erdogan seized on the US withdrawal to launch the offensive on US-allied Kurdish fighters in northern Syria. Mr Trump's move had sparked some of the most unified criticism of his administration to date, as politicians in both parties accused Trump of forsaking longtime Kurdish allies and inviting Russia and Iran to hold even greater sway in the volatile region. When the US forces withdrew, Syria's Kurds seeking protection from their number one enemy, Turkey invited Syrian government and Russian forces into parts of northeastern Syria where they had not set foot in years. More are now deploying along large parts of the border region under a Russian-Turkish deal, including to at least one former US garrison in northern Syria. The Ankara agreement required Syrian Kurds to vacate a swathe of territory in Syria along the Turkish border in an arrangement that largely solidified Turkey's position and aims. Mr Pence hailed the cease-fire as the way to end the bloodshed caused by Turkey's invasion. But Syrian-led Kurdish forces say the cease-fire is persistently violated. Meanwhile, Syria's Kurds have handed over an American toddler and three German children and their mother to their respective governments, a Kurdish official and a Kurdish source said on Saturday. After years of leading the battle against ISIS in Syria, the Kurds hold hundreds of foreign men, and thousands of related women and children suspected of links to the extremists. Abdelkarim Omar, a senior official with the Kurdish authorities in northeastern Syria, said the handover went ahead on Friday. "An American child and three German children with their mother were handed over to their governments," he said in a statement on Twitter. A Kurdish source said the American girl - who was born in 2016 - was handed over to a US official at the Samalka crossing with Iraqi Kurdistan, but could not provide any further details about her parents. Germany's <em>Bild</em> newspaper has reported the American child was the daughter of the German woman's first husband, who was a US citizen. Germany on Friday said it was repatriating its first ISIS suspect, and that she and her three German children had crossed into Iraq on their way home. <em>Spiegel </em>magazine named the mother as Laura H., 30, and said she and her children had been living in the overcrowded Al-Hol camp for the displaced in northeastern Syria.