Jamie Lynn Spears Fires Back at Britney, Says 'Accusatory' Posts Are 'Not the Truth' and Lead to Death Threats

Jamie Lynn Spears is publicly responding to sister Britney Spears' criticism of her recent TV interview.

Jamie Lynn, 30, shared a message on Instagram early Friday insisting that she "is always here" for her older sister while explaining the accusations Britney, 40, posts on social media "don't match" what is said between the sisters in private. She claimed Britney's posts lead to "death threats" against her family.

"Brit, I am always here for you, you know behind the scenes I have always been here. It's become exhausting when conversations, and texts we have in private don't match what you post on social media," Jamie Lynn wrote.

She added, "Quite frankly, the things being said are absolutely not the truth, and I have to clarify that, because now it's getting harder for me to rationalize to my oldest daughter why our family continues to get death threats, as a result of their aunt's vague and accusatory posts, especially when we know she could tell the truth, and put an end to all of it in one second if she wanted to."

RELATED: Jamie Lynn Spears: I Had to 'Separate Myself from My Family' but I 'Love and Support' Britney

Jamie Lynn also hit back against Britney's claims that she was selling her new memoir, Things I Should Have Said, at her sister's "expense."

She wrote, "I hate to burst my sister's bubble, but my book is not about her. I can't help that I was born a Spears too, and that some of my experiences involve my sister. I've worked hard since before I was even a teenager, and I've built my career in spite of just being someone's little sister."

Ending her statement, she wrote, "There are no sides, and I don't want drama, but I'm speaking my truth to heal my trauma, so I can close this chapter and move forward, and I wish my sister could do the same. No matter what comes, I will always love my big sister, and be here for her. It's time to put an end to the unhealthy chaos that has controlled my life for so long."

Phillip Faraone/FilmMagic; Michael Loccisano/Getty Images Britney Spears and Jamie Lynn Spears

RELATED: Britney Spears Unfollows Sister Jamie Lynn on Instagram — Days After Calling Out Family

Jamie Lynn's statement came shortly after Britney shared a lengthy reaction to the Wednesday ABC News interview special Jamie Lynn appeared in to promote her new book.

In the two-part segment, which aired on Good Morning America and Nightline, Jamie Lynn claimed she tried to help Britney end her conservatorship, which was terminated in November after 13 years. She also addressed Britney's mental state, claiming her sister had been "erratic" in the past.

Image Group LA/getty Britney and Jamie Lynn Spears in 2017

Britney revealed on Twitter Thursday that she watched the interview while sick with a fever, telling her followers she was bothered by Jamie Lynn's claims that her "behavior was out of control." Britney wrote, "She was never around me much 15 years ago at that time .... so why are they even talking about that unless she wants to sell a book at my expense??? REALLY???"

"Then where the lady mentioned why did she accuse you of doing remixes to her songs ... I know it may sound like a silly thing to most people but I wrote a lot of my songs and my sister was the baby," Britney added, referring to a moment in Jamie Lynn's interview with Nightline anchor Juju Chang. "She never had to work for anything."

RELATED: Britney Spears Calls Out Sister Jamie Lynn amid Book Release: 'She Never Had to Work for Anything'

The "Toxic" singer also accused her family of trying to "pull me down and hurt me always so I am disgusted with them."

RELATED VIDEO: Britney Spears Called the Day Her Conservatorship Ended 'The Best Day of Her Life': Source

Jamie Lynn has repeatedly insisted she supports Britney, while her older sister has denied her claims and previously accused her family of conservatorship abuse. Her father, Jamie; her mother, Lynne; and Jamie Lynn have all denied wrongdoing.

Britney said her conservatorship "killed" her "dreams" in a July Instagram post, writing, "I don't like that my sister showed up at an awards show and performed MY SONGS to remixes !!!!! My so-called support system hurt me deeply !!!!"

In June, Jamie Lynn appeared to support Britney after the singer made a statement in court asking for her conservatorship to be terminated.

"Since the day I was born, I've only loved, adored and supported my sister. I mean this is my freaking big sister, before any of this bulls—," Jamie Lynn said in a video shared to her Instagram Story.

She added, "I don't care if she wants to run away to a rainforest and have [a] zillion babies in the middle of nowhere. This situation does not affect me either way, because I'm only her sister who's only concerned about her happiness."

In this week's issue of PEOPLE, Jamie Lynn also said she's "only ever tried to be helpful, so any notion that says the contrary is just completely ridiculous."

For Jamie Lynn, "it was really important for me to separate myself from my family to focus on the family I've created, which is me, my husband and my daughters. Setting those boundaries in place was really important," said the Sweet Magnolias actress, who is raising daughters Maddie, 13, and Ivey, 3, with husband Jamie Watson, 40. "I am not my family. I am my own person. I fought very hard and worked very hard to establish myself and to build the life that I have today."

Things I Should Have Said is out Jan. 18. For more from Jamie Lynn Spears, pick up this week's issue of PEOPLE, on newsstands everywhere Friday.