it will take years to defeat the Islamic State militant group. He also said that airstrikes against the group have made it "much harder" for them to launch new attacks.Mr. Kerry spoke in Brussels, Belgium, at the opening of a meeting with foreign ministers to discuss efforts to fight the Islamic State. He said that the U.S.-led airstrikes will continue. There have been more than 1,000 airstrikes in Iraq and Syria since August.However, Syrian President Bashar al-Assad said U.S.-led strikes in Syria have made no difference in fighting Islamic State militants. The Syrian leader described himself Wednesday as a captain trying to save his ship.Mr. Assad also said, "You can't end terrorism with aerial strikes."A suicide car bomber has attacked United Nations vehicles in the Somali capital of Mogadishu. The explosion killed at least three people and wounded seven.The attack Wednesday happened near the city's international airport, which is home to some foreign embassies and a United Nations base.A U.N. spokesman said no U.N. workers were injured or killed.The militant group al-Shabab claimed responsibility for the attack.New information shows the Ebola outbreak is spreading faster in Sierra Leone than other West African countries.In its latest update Wednesday, the World Health Organization said Sierra Leone reported 537 new cases in the week ending November 30. That is 150 more than the number of cases reported the week before.The worst affected area was the capital, Freetown, where more than 200 new cases were reported.The WHO's latest report says the number of Ebola cases worldwide is more than 17,000. Almost all are in Sierra Leone, Guinea and Liberia. More than 6,000 people have died of the disease.Qatar has ended a travel ban against an American couple who were found innocent of any charges in the death of their daughter.The U.S. ambassador to Qatar posted on Twitter that the couple will be permitted to leave Qatar Wednesday. The ambassador said all requirements have been met to clear the way for their departure.The ambassador had been working with Qatari officials to let Matthew and Grace Huang leave the country.Eight-year-old Gloria Huang died in January of 2013. The couple was found guilty of child endangerment last March in connection with her death. But, on Sunday, a court in Doha cancelled that ruling.更多听力请访问51voa.com