ROME, June 23 (Reuters) - Prime Minister Mario Draghi put the Vatican on notice on Wednesday not to interfere with a parliamentary debate over a draft law designed to combat homophobia, saying Italy was a secular state. The Vatican earlier this month protested to the government over the contested bill, saying that in its present form it could restrict the religious freedom of the Catholic Church. read more But Draghi, a practicing Catholic, said parliament was free to discuss laws and legislate. "Ours is a secular state, not a religious state," he told the upper chamber Senate. He added that Italy also had checks and balances in the system to make sure it honoured its international obligations. "Our legal system contains all the guarantees to ensure that laws always respect constitutional principles and international commitments, including the concordat with the Church," he said. Draghi was referring to the 1929 Lateran Pacts, which established the Vatican City as a sovereign state and regulates relations between it and Italy. The Vatican, in a letter delivered to Italy"s embassy to the Holy See on June 17, argued that the draft law could undermine that accord. The Vatican fears that the law as written could lead to criminalisation of the Church in Italy for refusing to conduct gay marriages, for opposing adoption by homosexual couples through Catholic institutions or for refusing to teach gender theory in Catholic schools, according to a Vatican source. Supporters of the so-called "Zan bill," named after the openly gay legislator Alessandro Zan, criticised the Vatican for entering the political debate. "Parliament is sovereign and won"t accept interference," the speaker of the lower house, Roberto Fico, told state broadcaster RAI on Wednesday. However rightist parties which portray themselves as defenders of traditional values, welcomed the Church intervention. "I thank the Vatican for its good sense," said Matteo Salvini, head of the League party.