Photographs of female FARC fighters illustrate life before and after the recent peace deal with the Colombian government.

After four years of negotiation, last month the Revolutionary Armed Forces of Colombia (FARC) and the Colombian government signed a ceasefire deal ending a guerrilla war that began over 50 years ago.

On Friday Colombian President Juan Manuel Santos was awarded the Nobel Peace Prize for his efforts to end the war, which has killed some 220,000 people and displaced eight million.

In order to come into force, the agreement signed by Santos and FARC leader Timoleon "Timochenko" Jimenez had to be ratified by the Colombian people in a referendum.

© AP Photo / Fernando Vergara This Aug. 13, 2016 photo shows two portraits of Diana Marcela, one of her holding a weapon while in uniform for the 32nd front of the Revolutionary Armed Forces of Colombia (FARC), and in civilian clothing at a guerrilla camp in the southern jungle of Putumayo, Colombia

© AP Photo / Fernando Vergara This photo, taken on August 13 2016, shows two portraits of Yiceth

However, the deal has an uncertain future after the public narrowly voted to reject it on Sunday. Just over half, 50.22 percent of voters opposed the deal, as opposed to 49.78 percent of voters who were in favor. There was a low turnout for the referendum, with less than 38 percent of voters casting their votes.

Around 40 percent of FARC's guerilla army is comprised of women, a notably high proportion. FARC's revolutionary ideals are based on Marxist-Leninist principles and include equal rights and responsibilities for men and women.

These portraits illustrate how signing the peace deal changed life for these female FARC fighters, who laid down their arms as a result of the agreement.

© AP Photo / Fernando Vergara This photo, taken on August 13 2016, shows two portraits of Yeimi

© AP Photo / Fernando Vergara This photo, taken on August 15 2016, shows two portraits of Sofia

© AP Photo / Fernando Vergara This Aug. 15, 2016 photo shows two portraits Carolina

© AP Photo / Fernando Vergara This Aug. 16, 2016 photo shows two portraits of Yuri Renteria

© AP Photo / Fernando Vergara This Aug. 15, 2016 photo shows two portraits of Derly

Marcela Velasco, Professor of Comparative Politics at Colorado State University, told Radio Sputnik that the deal was rejected because of concerns about a lack of accountability from the FARC for crimes committed during the 52-year guerilla war.

Many Colombians "did not approve of the transitional justice," Velasco said.

© AP Photo / Fernando Vergara This Aug. 16, 2016 photo shows two portraits of Mayerli

© AP Photo / Fernando Vergara This Aug. 15, 2016 photo shows two portraits of Rubiela

Regional politics also played its part in the deal's rejection. Those regions mostly affected by the long-term conflict supported the "yes" vote. Those areas that did not have to deal with the violence on a daily basis, the more conservative regions, voted against, Velasco said.

The professor is confident that FARC, which has provided the government with lists of their members, agents and supporters, will not restart the violence.

"The FARC so far has been very clear that they are going to wait it out […] and maintain their promise of talking, of negotiating, which means that they are not going to war," she said.

For his part, Colombia President Juan Manuel Santos, who was awarded the Nobel Peace Prize for negotiating the agreement, said that he "will continue seeking peace until the last day of my presidency."