Feb 19 (Reuters) - The chief executive of Uber Technologies Inc has ordered an "urgent investigation" into claims of sexual harassment raised by a former engineer in a blog post.

Susan Fowler, who left Uber in December, wrote that she was subjected to sexual advances through a 'string of messages' over the company's chat software from the beginning of her employment. http://bit.ly/2kCE416

"What she describes is abhorrent and against everything Uber stands for and believes in," CEO Travis Kalanick said on the Twitter microblog on Sunday in response to the Folwer's post. He said he had instructed Chief Human Resources Officer Liane Hornsey to conduct an urgent investigation.

Fowler wrote that Human Resources told her the person "was a high performer" and that management would not be comfortable in "giving him anything other than a warning".

Arianna Huffington, editor-in-chief of The Huffington Post, said in a tweet that as a representative of Uber's board of directors, she would work with Hornsey in the investigation.

The San Francisco-based company was not immediately available for comment.

(Reporting by Vishal Sridhar in BENGALURU; Editing by Christopher Cushing)