Catholics for Choice, a Washington-based liberal advocacy group, urged Pope Francis Wednesday to allow people to use contraception or let women have abortions to protect themselves against the Zika virus. The virus has suspected links with microcephaly, a birth defect in which babies are born with abnormally small heads and underdeveloped brains.

The group issued a statement saying it would run ads about the message to the pope in the International New York Times and El Dario de Hoy in El Salvador on Thursday ahead of Francis’ trip to Cuba and Mexico. The Catholic Church views abortion as killing and bans the use of artificial birth control methods such as condoms.

"Pope Francis has an opportunity to reverse a longstanding injustice on this trip," Jon O'Brien, president of Catholics for Choice, said in a statement. "If he wants a church that lifts up the poor, he must remove the birth control ban that falls so harshly on the women of Mexico and Central and South America, and allow women to make a decision about their pregnancies," O’Brien added.

Until recently, the Zika virus spread was limited to a handful of countries in equatorial Africa and Asia. It first appeared in Brazil last May and since then, an estimated 1.5 million people are believed to have been infected in the country alone. The virus has also spread across the Americas.

The World Health Organization declared an international emergency over the virus on Feb. 1, citing an unproved but strongly suspected link between the Zika virus and microcephaly. Researchers have warned that the virus could become a pandemic if not controlled on time.