Pro-abortion demonstrators vandalised Chile's main cathedral during a Mass and used pews as barricades during clashes with police.
A group of demonstrators broke off from a largely peaceful protest calling for the legalisation of abortion and stormed into the Metropolitan Cathedral of Santiago, interrupting the homily.
They painted walls with pro-abortion messages, broke ornaments and hauled pews all the way to the Plaza de Armas square in front of the cathedral. Police in riot gear rushed to the cathedral to contain them, and arrested at least two people.
President Sebastian Pinera condemned the vandalising of the cathedral, which remains closed for repairs.
"We repudiate and reject these types of acts," Mr Pinera told reporters outside the presidential palace. "This means not respecting the rights of others," he said. "They're not tolerant and are contradicting their own views."
Abortions, even for medical reasons and in the case of rape, have been illegal since General Augusto Pinochet's dictatorship, which ended in 1990. Mr Pinera's government opposes any easing of the ban.
The gaffe-prone president recently caused an uproar when he praised an 11-year-old girl for her "depth and maturity" after she said in a TV interview that she wants to give birth to the baby who was conceived when she was raped by her mother's partner.
The case has inflamed already heated national debate over abortion in one of Latin America's most socially conservative nations. The Chilean Senate rejected three bills last year that would have eased the absolute ban on abortion.
Former President Michelle Bachelet, the frontrunner in the November 17 presidential elections, favours legalising abortion in cases of rape or risks to the health of the mother or the child. She spent the past several years heading the UN agency for women.
Her opponent, former Labour Minister Evelyn Matthei has angered elements of her own party by advocating for abortions when a mother's health is in danger. But she said recently that she would not propose easing the ban on abortions if she becomes president to avoid a conflict within her conservative coalition.