Kabul, AFGHANISTAN -- An attack in Kabul, Afghanistan, has killed at least 40 people and injured more than 30 more on Thursday.
Kabul has seen an increase in attacks on Shia mosques or cultural centers by ISIS members.
U.S. Vice President Mike Pence made a surprise appearance in Afghanistan on Dec. 21 to rally troops stationed in Kabul. Pence reiterated U.S. support for the war in Afghanistan, saying the U.S. was "here to see this through."
"It's because of all of you that we're safe. It's because of you that we're free. It's because of you that freedom has a future in Afghanistan and America and all across the wider world," Pence said.
The U.S. has about 15,000 troops stationed in Afghanistan, according to the Defense Manpower Data Center.
ABC News' Mark Osborne contributed to this report.