Oxford University has apologized for an image of a female worker cleaning chalk that read "Happy International Women's Day" at the university's campus. Sophie Smith, an associate political theory professor at the college, tweeted the image Thursday.

What an image for [International Women's Day]," Smith wrote.

The image has been retweeted nearly 20,000 times on Twitter.

Oxford security makes a woman cleaner scrub out “Happy International Women’s Day” on the Clarendon steps. What an image for #IWD, @UniofOxford. #strikeforUSS #UCUstrike pic.twitter.com/E9u5S37hWW — Sophie Smith (@DrSophieSmith) March 8, 2018

The university responded to the image about an hour later on Twitter, apologizing for the incident.

We are deeply sorry for this and for offence caused. International Women's Day is hugely important to Oxford. This should not have happened. — Oxford University (@UniofOxford) March 8, 2018

Smith thanked the university for the apology but said they owe the female worker a little bit more following the gaffe.

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"I appreciate your apology, but far more importantly can you please make sure that the woman asked to remove the message receives a heartfelt apology, a warm cup of tea, the rest of the day off and, along with all our precarious staff, good enough pay to live in this city," Smith replied.

Garrick Taylor‏, president of the Oxford University and College Union (UCU), questioned why the chalk needed to be cleaned immediately after a rally celebrating International Women's Day.

"During a peaceful International Women's Day rally. A low paid and probably precariously employed female cleaner was sent out in the freezing cold to clean chalk writing saying Happy International Women's Day. Did it have to be removed? Then?," Taylor said on Twitter.

The university did not immediately respond to CBS News' request for comment.