The Vatican is watching the sex scandal engulfing the Italian prime minister, Silvio Berlusconi, “with concern,” its secretary of state, Cardinal Tarcisio Bertone, said Thursday, the news agency ANSA reported. The cardinal’s remarks are a sign of Mr. Berlusconi’s growing political weakness a week after prosecutors began investigating whether he compensated “a significant number” of women, including a minor, for sex. The prime minister denies all wrongdoing. According to ANSA, Cardinal Bertone said the Roman Catholic Church urged greater “morality” and “legality” in public life, especially from those holding public office. His remarks were seen as lending support to centrist politicians who seek to oust Mr. Berlusconi. In a television interview on Wednesday, the minor, Karima el-Mahroug, denied that she had sex with Mr. Berlusconi or asked for money in exchange for her silence, as wiretapped phone conversations published in the Italian news media this week suggested.