It remains unclear as to whether the tunnel was meant to eventually lead to Turkey, as it splits into two different directions. However, a tunnel linking Syria to Turkey may offer new answers as to how so many terrorists have been able to slip across the border to fight alongside IS.
According to a US State Department report, over 16,000 foreign fighters slipped into Syria to join IS in 2014, with Turkey serving as the "main transit route" for them.
The seizure of Tal Abyad was hailed as a major strategic victory for the YPG, as it cuts off a vital supply line to IS’ proclaimed capital, Raqqa. The victory comes after intense clashes between Kurdish and IS fighters that prompted some 23,000 Syrian refugees to flee to Turkey.
Turkish officials say the YPG had closed the border from the Syrian side on Wednesday after they captured the town, but the Kurdish group denies the claim. According to local authorities, the official border between Syria and Turkey reopened on Monday, allowing Syrian refugees to return.
"Refugees have been crossing back into Syria since this afternoon after the YPG re-opened the border," an official from the Turkish prime minister’s office said.
No details have been given on the flow back of refugees to Syria, but Turkish news agency DHA puts the number at 500.