The United Nations humanitarian chief said on Wednesday that the Baba Amr district of Homs is deserted after the massive assault launched against its residents by Syrian President Bashar al-Assad. The neighborhood had been considered one of the birthplaces of the uprising against Assad, and activists said the government is trying to cover its atrocities there. Wednesday’s visit to Baba Amr by U.N. humanitarian chief Valerie Amos is the first time an independent observer has been allowed into Syria since the monthlong crackdown on Baba Amr began. Meanwhile, the country’s deputy oil minister, Abdo Hussein, defected on Wednesday, according to a video posted by activists. In the video Hussein declared, “I join the revolution.” He is the highest-level government official to defect from Assad’s regime so far. U.S. officials said Wednesday that President Obama is weighing military action in Syria.