U.S. President Barack Obama on Friday signed into law an act that bars entry of certain representatives to the United Nations. The act, passed by the U.S. Congress last week, is aimed at blocking Hamid Aboutalebi, Iran's newly appointed ambassador to the UN, from entering the United States. Lawmakers sponsoring the act said Aboutalebi should be banned from entry to the United States because he was a member of a militant group that held 52 Americans hostage when it seized the U. S. embassy in Tehran in 1979.