Clothing retailer Urban Outfitters has apologized for selling a red-splattered sweatshirt that referenced an Ohio university where four students were shot dead in 1970.

The "vintage Kent State Sweatshirt" had initially been listed for sale on the Urban Outfitters website for $129. The bleached pale red sweatshirt featured the words "Kent State University," circling a mock university logo and red splotches of paint that closely resembled blood stains. The shirt also had several holes in it. The company has since removed the clothing item from its website.

Many were angered that the shirt appeared to be referencing a 1970 shooting at Kent State University that left four student protesters dead and nine others wounded.

On May 4, 1970 members of the Ohio National Guard opened fire on unarmed students who were protesting at Kent State against the Vietnam War. The shooting sparked a massive nation-wide student strike and affected public opinion over America's involvement in the war.

The university issued a statement on Monday, saying that it was greatly offended that Urban Outfitters would use the "watershed moment" for its "publicity and profit."

"This item is beyond poor taste and trivializes a loss of life that still hurts the Kent State community today," the statement said.

Urban Outfitters also issued a statement Monday, apologizing for any offence the sweatshirt may have caused. It claims that it never meant to reference the school shooting.

"It was never our intention to allude to the tragic events that took place at Kent State in 1970 and we are extremely saddened that this item was perceived as such," the statement said.

The company said the shirt was part of their "sun-faded vintage collection," and the red splotch marks were the result of "discoloration" from the original red shade of the shirt. The holes in the shirt are the result of "natural wear and fray," the company said, adding that there is no blood on the item.

But as images of the shirt spread, many on Twitter expressed outrage over the shirt's design. Many even accused the company of purposely designing the shirt to offend and shock, in a bid to net sales.

This isn't the first time the clothing company has made headlines for some of its design choices.

Last January, the company pulled a controversial "depression" T-shirt from its shelves . The white crop top, which had the word "depression" printed on it multiple times, prompted a backlash from critics who accused the company of trying to use mental illness to make a fashion statement.

The company also came under fire in 2010, for selling a T-shirt that said "Eat Less." That shirt was also quickly pulled. That same year, the company pulled a T-shirt from its online store that came in a colour option called "Obama/Black."