Lars Maischak, an American history professor at Fresno State University in California, apologized again Thursday for a tweet he posted on February 18 that said President Donald Trump 'must hang' to save American democracy

An American history professor at Fresno State University in California apologized again on Thursday for a tweet he posted on February 18 that said President Donald Trump 'must hang' to save American democracy.

The professor, Lars Maischak, said he has temporarily left Fresno while the university is on spring break, after receiving death threats and hundreds of hate emails since the tweet was highlighted by far-right websites such as Breitbart News.

'I regret making these tweets,' Maischak said. 'I wrote them to an audience of 28 followers on Twitter under the assumption they would be read by people I know.'

Maischak said he sent the tweet in February to voice personal despair over comments by Trump and actions by the current U.S. government and was not trying to incite violence.

The tweet said: 'To save American democracy, Trump must hang. The sooner and the higher, the better. #TheResistance #DeathToFascism.'

Breitbart posted an article Saturday saying the tweet and others on Maischak's account showed opinions that 'explain why universities across the country are now viewed with disdain by the average, salt-of-the-earth Americans.'

The tweet said: 'To save American democracy, Trump must hang. The sooner and the higher, the better. #TheResistance #DeathToFascism'

Maischak deleted his Twitter account on Wednesday and said he is prepared to take full responsibility for his statements.

Fresno State has distanced itself from the comments, saying they reflect Maischak's personal views and not those of the university.

University President Joseph Castro said he appreciated Maischak's apology, calling it 'a first good step' in calming critics, the Fresno Bee reported.

The university was committed to free speech and was taking the matter seriously, Castro said. He said officials had contacted federal authorities, adding his main concern is the safety of students and the campus community.

Maischak deleted his Twitter account on Wednesday and said he is prepared to take full responsibility for his statements

Maischak first issued an apology for his actions in the form of a written statement published by the Fresno Bee on Wednesday.

'I apologize for the tone and content of my statements made on Twitter,' the statement read.

'I ask forgiveness of those who felt threatened or offended by them. It was never my intent to harm anyone, nor to encourage others to harm anyone. My statements each represent the end point of a dark train of thought triggered by my despair over the actions of the present US government. That is what I meant by calling them "dark predictions." It felt cathartic at the time to write them down.

Now under federal investigation, Maischak said he is keeping the Secret Service abreast of his whereabouts, he said; President Donald Trump is seen here in the Roosevelt Room of the White House in Washington, DC on Thursday

'With 28 followers on Twitter at the time, I never expected them to be read by anyone but a close circle of acquaintances who would know to place them in their context. To treat Twitter as of no more consequence than a journal was a poor decision. I have deleted my Twitter account, to preclude the possibility that anyone reading my statements in the future would take them as encouragement to act violently or unlawfully. In this spirit, I am prepared to take full responsibility for my statements.'

Following Maischak's apology, the president of Fresno State University released this statement:

'I appreciate Dr. Maischak’s apology and willingness to take accountability for the statements made on his Twitter account. In his note to me, Dr. Maischak reiterated that it was not his intent to incite violence or harm others, however, Fresno State has a responsibility to continue a review of the situation. As previously stated, the University takes this matter seriously and is handling it in accordance with applicable law, policy and the requirements of the faculty collective bargaining unit agreement.'

Now under federal investigation, Maischak said he is keeping the Secret Service abreast of his whereabouts, he said.

'I am not in Fresno. I fear for my life,' the professor said, adding that when school resumes next week his classes on Monday and Tuesday will be canceled.