Yonhap news agency cited an unidentified U.N. source. Yonhap quoted another unidentified U.N. source as saying Ban’s trip could serve as a breakthrough in the standoff over North Korea’s nuclear weapons program and strained ties between the two Koreas. Yemeni security officials say Saudi-led air strikes and clashes have killed some 40 Shiite rebels and their allies. Yemen’s fighting pits the rebels, known as Houthis, against forces loyal to the internationally recognized government. Rio de Janeiro police said Monday that they are investigating the apparent mob killing of a 33-year-old ice vendor in the heart of the Olympic city’s Ipanema neighborhood. Police said they have spoken to witnesses and requested surveillance videos to shed light on the circumstances of Fabiano Machado da Silva’s death on Sunday. The visit follows Chinese protests over the sailing last month of a guided missile destroyer within 12 nautical miles of disputed Subi Reef. Zimbabwe’s prisons are woefully funded, with prisoners, former prisoners and even prison officials often complaining about food shortages. A riot broke out at the country’s largest maximum-security prison, Chikurubi prison in Harare, in March over food shortages, in which officers shot dead five prisoners.