Thousands of Polish pro-lifers have called on parliament to pass a bill that would further restrict abortion in the country.

"Today we are calling on our state authorities to guarantee full legal protection of unborn children," Pawel Kwasniak said to a Sunday rally of over 1,000 people in Warsaw.

Kwasniak heads the Support Center for Life and Family Initiatives, the Warsaw-based pro-life NGO that organized support for the proposal.

Rallies in favor of the proposed bill were held in 140 cities and towns across Poland May 15, organizers said. Backers of the bill include Jaroslaw Kaczynski, who heads Poland's ruling Law and Justice party, and Prime Minister Beata Szydlo.

The proposed citizen's bill would allow abortions only to save a women's life. It would increase the maximum prison sentence for unauthorized abortions from two years to five. Those who provide information about or arrange for a legal abortion abroad could be liable as an accessory to the act, Deutsche Welle reports.

In June 2011 backers of a similar proposal gathered over 500,000 signatures in support, but the bill was defeated by a majority of MPs. Citizens must gather over 100,000 valid signatures by the end of June to oblige parliament to proceed, Agence France Presse reports.

Since 1993, Poland's abortion law allows abortions only for pregnancies that result from rape or incest, that pose a risk to the health of the mother, or that involve a severely deformed unborn baby.

Three former first ladies of Poland opposed the bill in a letter. These include Danuta Walesa, the wife of former president, Nobel Prize winner, and Solidarity leader Lech Walesa.

Some abortion proponents are seeking 100,000 signatures to make Poland's abortion law more permissive.

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About 700-1,800 legal abortions take place in Poland each year.