The U.N. Office of Counter-Terrorism is launching a new program to help countries detect and disrupt travel by foreigners who have fought for extremist groups such as Islamic State and al-Qaida.

U.N. Secretary-General Antonio Guterres said Tuesday that the U.N. Countering Terrorist Travel Program uses a new "goTravel" software system to collect, process and share passenger information with national and international authorities.

He said that after the defeat of IS in Syria and Iraq, many of the more than 40,000 foreigners estimated to have fought there are trying to return home or relocate to safe havens where they could carry out terrorist attacks and recruit new followers.

Guterres says that "detecting and disrupting these terrorists and other high-risk criminals ... is a high priority for the international community."