An armed standoff is continuing at a mall in Nairobi, Kenya, where al-Qaeda-linked militants have taken hostages in a deadly rampage. At least 68 people have died and nearly 200 have been wounded since armed gunmen with Somalia’s al-Shabab stormed the shopping center on Saturday. Explosions and black smoke were seen at the mall today as Kenyan forces tried to enter. Al-Shabab says it launched the attack in response to Kenya’s role in the African Union peacekeeping force in neighboring Somalia. Kenyan forces entered Somalia two years ago to help the fight al-Shabab militants. At the United Nations, Secretary-General Ban Ki-moon condemned the attack.

U.N. Secretary-General Ban Ki-moon: “I condemn in the strongest terms yesterday’s terrorist attacks in Nairobi’s Westgate Mall. This premeditated act targeting defenseless civilians is totally reprehensible. The perpetrators must be brought to justice as soon as possible. Scores have been killed and wounded. I express my condolences to families of the deceased and injured and to the loved ones of all those of other nationalities who are among the victims.”

There have been unconfirmed reports at least three of the al-Shabab gunmen are Americans. The assault on the Westgate Mall marks the worst single attack in Kenya since the bombing of the U.S. embassy in 1998.