LONDON, Sept 18 (Reuters) - ⁠English third-tier club Oxford United have withdrawn ⁠a clothing line featuring the slogan "United 93" ‌and apologised for being unaware of its historical context.

United 93 was the call sign of one of the passenger jets ​hijacked in the 9/11 Al ⁠Qaeda attacks on the ⁠United States in 2001.

The merchandise was intended as ⁠a reference ‌to the club's founding year of 1893.

"The range was released without understanding ⁠of the historical context and associations," a ​club statement ‌read.

"It should not have reached the point of ⁠sale and ​we take full responsibility for not undertaking proper due diligence.

"We have removed the collection with immediate effect ⁠and are reviewing our approval ​processes to ensure nothing like this happens again. Once again, we would like to put on record ⁠our sincere apologies for this error and for any offence caused."

United Airlines Flight 93 crashed in Shanksville, rural Pennsylvania, killing all 44 people on ​board, after being hijacked on ⁠September 11, 2001.

It is believed the plane was ​heading for the US Capitol ‌Building before passengers attempted to ​regain control -- the tragedy chronicled in the 2006 docudrama movie "United 93".

(Reporting by Martyn Herman)