Several countries continued to condemn Friday a twin suicide attack that rocked Beirut's southern suburb one day earlier, claiming the lives of 43 people and wounding 239 others. Washington deplored the attack carried out by ISIS in Burj al-Barajneh neighborhood, extending its "deepest condolences to the Lebanese people, in particularly the families of the victims." The attack is a "troubling reminder of the tremendous challenges Lebanon still faces," State Department deputy spokesman Mark Toner said in a statement. The statement denounced "terrorism," saying it "seeks to undermine the freedom and security that the people of Lebanon have worked so hard to achieve," reiterating its full support and commitment to the Lebanese state that is waging a war against "terrorism." U.N. Secretary-General Ban Ki-moon strongly condemned the attack. Ban expressed in a statement his deep sadness over the "high numbers of fatalities and injured, and extends his condolences to the families of the victims and to the people and government of Lebanon." He hoped that such "despicable" acts would not "destroy the relative calm that has prevailed in the country (Lebanon) over the past year," calling on the Lebanese political spectrum to "preserve Lebanon's stability and security." Lebanon Friday witnessed a day of mourning over the bloody attack in the busy residential and commercial area. U.N. Special Coordinator to Lebanon Sigrid Kaag described the attack as "heinous," urging the Lebanese to maintain "unity, stability and security." "The international community stands by Lebanon," she added. On Thursday French President Francois Hollande condemned in a statement issued by his office the blasts, expressing "his indignation and horror following the attack which killed several dozen people and wounded more than 100 in the Burj al-Barajneh neighborhood of Beirut."