NASHVILLE (AP) — Tennessee's House speaker pushed back Wednesday against calls to abandon his top legislative leadership post from Democratic and Republican lawmakers, releasing a plan intended to restore trust in his office.

House Speaker Glen Casada has faced increased scrutiny after his top aide, Cade Cothren, stepped down earlier this week amid allegations he sent racist and sexually explicit text messages. Cothren also acknowledged using cocaine in his legislative office several years ago.

As pressure built, a handful of Republican members expressed outrage at the speaker's handling of the allegations against Cothren, and added they were uneasy over his admitted participation in the text messages with him.

As of Wednesday, four GOP House members and one GOP Senate member had joined Democratic support of calls for Casada to resign as speaker.

However, Casada rebuffed those calls and instead organized an emergency conference call with the GOP House caucus to quell concerns.

"I take complete ownership over the text messages with inappropriate comments about women that I exchanged with my former chief of staff and another individual several years ago," said Casada in a statement shortly after the call adjourned. "It's embarrassing and humbling to have it displayed in this manner."

Along with the lengthy statement, Casada released a four-point plan for regaining trust. It included asking the House Ethics Committee to review the termination of Cothren, as well as conducting a review of legislative policies and consideration of drug testing for new employees.

Casada also said he asked the Tennessee Bureau of Investigation and the District Attorney Generals Conference about Cothren possibly tampering with evidence in a criminal case involving a young black activist, who was arrested earlier this year at the Capitol during a protest.

Casada's open acknowledgement of the racist and sexually explicit text messages was a stark difference from defensive remarks he had given this past week, in which he initially questioned if the texts had been fabricated.

News of the leaked text messages first broke last week after a news outlet asserted Cothren may have participated in evidence tampering and transmitting racist text messages.

"I've never in those 10 years known any kind of racist or bigoted action out of him and so if an individual is willing to run a story that's not true about receiving emails, what else are they making up?" Casada had told reporters last week.

Then, on Monday, more text messages were released showing that Casada and Cothren had exchanged sexual explicit text messages about women nearly three years ago.

Cothren quickly resigned, though Casada told The Tennessean that his own explicit texting was a comment on "a relationship between two consenting adults."

By Wednesday, Casada asked for forgiveness, saying he was a changed person and described those conversations as "locker room talk."

Meanwhile, Cothren never acknowledged sending the racist text messages, but was quoted by the Tennessean newspaper as saying that he had sent "derogatory" messages to women in the past. He told The Associated Press that he could not remember the content of all his past messages, but that he had done some things in the past "that I'm not proud of."

Rep. Jeremy Faison was one of the Republicans calling for Casada to resign from his speakership.

"I see no way possible for him to be an effective leader in this state moving forward," Faison told the AP.

Republican Gov. Bill Lee has declined to say if Casada should resign, but has described the recent events as disturbing and intolerable.

"Racist slurs, illegal activity, objectification of women, those themselves are not the higher standard," Lee told reporters earlier Wednesday. "Those who choose to be in public service have a higher responsibility to stand against those things."

House speakers in Tennessee serve two years before seeking reelection. Casada has only been in office since January.

He received 47 secret-ballot votes out of 73 Republicans in the 99-member chamber to become speaker-elect in November. Then the majority leader, he defeated Reps. Curtis Johnson of Clarksville and David Hawk of Greeneville.

"Democrats' only hope is for Republican division or scandal, and you will have neither with me. I don't play political games," said Rep. Curtis Johnson, during the GOP caucus elections in November.

Separately, Casada has also faced allegations of spying on legislative members — which he has adamantly denied. However, House Democrats have sent a complaint to the U.S. Attorney's office requesting an investigating, which has been referred to the FBI.