Two teenage sisters in Laos who converted from animism to Christianity have shared how their family members beat them, tied them up, locked them out of the house, and left them there for four days -- but their faith remains unshaken.

17-year-old Nani and 16-year-old Nha Phong converted to Christianity in autumn 2016 after hearing the truth of the gospel from a family member.

"My cousin told me about the Good News," Nani told persecution watchdog Open Doors. "He is a pastor in a church located in a village near ours. I liked what I heard very much, and that's why I became a believer."

The sisters soon became involved in their local church -- but their newfound faith didn't come without repercussions. The girls' parents and extended family members, devout animists, strongly opposed their decision to become followers of Jesus.

"When we went to church one time, our family became very angry at us. They told us not to go. My cousin and nephew said I needed to go back to my old religion, and if I didn't they would hit me and force me out of the church," said Nani.

That time, the cousin did not fulfil his threat. But three weeks later, when the girls left for church, their family members - around six to nine people - followed them secretly­ and dragged the sisters out of the worship service

"They tied us up and my dad hit my sister, but he didn't hit me. I don't know why," Nani recalled.

They took the sisters back to their village, where they were separated and kept tied up for several days.

"They took me to my uncle's house and asked me over and over again: 'Do you still believe in God?' They threatened me and told me that unless I renounced my new faith, they would keep me tied up," said Nha Phong.

Eventually, after four days, the sisters were released.

"Our family was still very upset over our decision to stand firm in our faith in Jesus," Nha Phong said.

Despite such persecution, the girls say their faith is stronger than ever.

"I believe that our strength to stand firm is a gift from God. God gave us the passion to believe," said Nani. "There is a Bible verse in Ephesians 6. When people fought in the past, they used a shield, and I want to have faith like a shield. When the evil one tries to shoot arrows at us, I will use the shield to protect me. So I have to put my faith in Jesus."

While Nani and Nha Phong's father is still opposed to his daughter's religion, his wife has shown interest in Christianity and even followed her daughters to church on occasion.

"Our mother never hit us, but our father did. He did this after the head of the village told him to. Dad listened to the authorities who did not want us to go to church," said Nani. "He didn't want my Bible in the house, so he took my Bible and hid it somewhere I couldn't find it. I found it later, so now I can read my Bible again."

"It has been really hard to not obey our father, who is the head of the family. But we want to obey Jesus more than anyone. We know that Jesus died for us, and we do not want to go back to our old religion. Even if it is difficult, we want to follow Jesus," she added.

While the girls have been able to go to church for Sunday service from time to time, they continue to face persecution.

"The head of the village told our mum that if we, her daughters, continue to go to church, they will throw us in jail. They said that we should get out of the village," said Nha Phong.

In May, authorities arrested the girls along with seven other Christians. Shortly after, the sisters were released, and they escaped to another village. Today, they live in their Christian cousins' village.

Because Nha Phong cannot read, she's only able to hear the Word of God when she's able to come to Church.

"But I believe in my heart," she said.

Open Doors asks believers around the world to pray that Nani and Nha's mother, father and cousins will come to believe in Jesus; that God will give the girls the strength and courage to stand firm; and that Nha will be able to learn to read and write so that she can read the Word of God for herself.

Laos is ranked 24 on Open Doors' World Watch List of countries where believers face the most persecution, and has received the maximum score in the violence category.

Buddhists make up more than 57 percent of the population of the Communist country, according to Operation World. About 35 percent of the population adheres to indigenous religions, and only 3.4 percent of the population is Christian.

Open Doors notes that Buddhism, animistic beliefs and practices, is deeply ingrained "in the thinking and culture of society."

"Every deviation from it is unthinkable and perceived as dangerous," says the outlet. "Therefore, Christians refusing to participate in Buddhist practices are perceived as foreign and a threat to traditional culture. Witnessing to Buddhist neighbors and family can be a huge challenge, but believers here are boldly living out their faith."