HALIFAX -- Nova Scotia Premier Stephen McNeil says his campaign communications director resigned because he felt "under attack" after the Tories questioned the appropriateness of hiring someone convicted of domestic assault.

The resignation by communications aide Kyley Harris on Tuesday came a day after the Liberals dropped Pictou East candidate Matthew MacKnight over 2013 comments on social media.

McNeil said he didn't talk to Harris before he resigned, and added the aide had made a personal decision.

"I believe he thought the issue that was brought forward was used by other political parties to attack my record," said McNeil. "My record on women, I'm very proud of it -- it stands by itself -- and he (Harris) needed to continue to try to put his life back together and he wanted to do it outside the public eye."

In a letter to campaign chairman Chris MacInnes, Harris said he had tried to make amends, but "it is clear that is not possible in the current political climate."

Harris said he can accept that he will continue to be punished for the 2014 incident, but did not want his colleagues and McNeil "to bear that burden any longer."

MacKnight was ousted late Monday as a candidate in the May 30 election after MacInnes said he was made aware of unspecified "highly inappropriate" comments.

MacKnight issued a brief statement Tuesday saying he takes full responsibility for the tweets and didn't intend for them to be derogatory or hurtful.

MacKnight apologized to two groups that represent people with Down syndrome, saying "it was an immature comment" that was not meant to be malicious.

"I cannot believe I made such comments. I have grown, and matured as a person since that incident," MacKnight said in the statement.

Global News linked to a photo of the alleged tweet, which had MacKnight purportedly calling someone an expletive and using the hashtags .downsyndrome and .stupidcustomers on May 28, 2013.

McNeil said MacKnight's comments were "inappropriate," and said candidates have to be mindful they are seeking elected office.

The premier drew a chuckle from several Liberal candidates who had gathered for an announcement Tuesday when he was asked whether the episode would change the party's Twitter policy.

He said nothing formal is planned, but he has often offered candidates advice.

"Stop doing it (tweeting)," McNeil said. "It can at times be completely be taken out of context. That's one of the challenges, you have very few characters to explain yourself ... and then you are spending as much time trying to defend that."

Progressive Conservative Leader Jamie Baillie endorsed the decision to remove MacKnight.

"His comments were not only offensive, they were mean-spirited and targeted or made light of the situation of some of our most vulnerable Nova Scotians," he said Tuesday. "It's becoming a bit of a circus show coming out of the premier's office, to be perfectly blunt."

He said it was appropriate for Harris to quit because his actions "lower the dignity of the office of the premier" and send a hurtful message to victims of domestic abuse.

"You're sending a message to all Nova Scotians by that hiring that is one of despair for so many survivors of domestic assault who believe their government is not there for them," he said.

NDP leader Gary Burrill said engaging Harris in a key campaign role, coupled with McNeil's earlier comments about women and winnable ridings, has "put the premier in a position where there are questions that reasonable people would like to have answered."

Last week, McNeil defended his decision to reinstate Harris, who had pleaded guilty to the assault charge.

McNeil said Harris deserved "a second chance" after being handed a conditional discharge for striking a woman in the face during a domestic argument on May 9, 2014.

The matter resurfaced after federal Conservative Leader Rona Ambrose said on social media that his re-hiring sends a "terrible message," and that Liberal leaders "need to walk the talk on violence against women."

In his letter, Harris said he was grateful he had been given a second chance.

"That the opportunity was offered to me in the first place is a testament to the character and humanity of Stephen McNeil," he told MacInnes. "It is rare for anyone -- let alone a politician seeking re-election -- to have shown the bravery and loyalty Stephen has shown me throughout my efforts to rebuild my life from what was a grievous error in judgement."

Also Tuesday, Burrill brought up the Tories' candidate in Hammonds Plains-Lucasville, Matt Whitman, who Burrill said has demonstrated "a not altogether stellar capacity for judgment."

In a photo posted to Twitter, Whitman is pictured dressed as a Mexican Donald Trump. He is wearing a red Trump baseball cap and a colourful woven poncho.

Whitman also found himself in hot water recently for using racially insensitive language after he posted a video showing him yelling "Chinese fire drill!" as he and a friend scrambled from a car.

Baillie said Tuesday he stood by Whitman's candidacy, but also distanced himself from the Twitter photo.

"Look that's not my style, but I don't think that's a firing offence," he said.