US President Barack Obama expressed condolences over the death of former New York mayor Ed Koch on Friday, calling him a "quintessential New Yorker" and an "extraordinary mayor.""[Koch's] energy, force of personality, and commitment to causes ranging from civic issues to the security of the state of Israel always informed and enlivened the public discourse," he said. "Michelle and I send our thoughts and prayers to Ed’s loved ones, and to the city that survives him."