MEXICO CITY, May 23 (Reuters) - Mexican state energy company Pemex produced 1.47 million barrels per day (bpd) of crude oil in April, the highest level in 45 years, data published by the country's hydrocarbon regulator showed.

Pemex's crude oil production fell 5.9% year-on-year and 12% since December 2018 when President Andres Manuel Lopez Obrador, who had promised to rescue the company, took office, data released on Tuesday showed.

Production of liquid hydrocarbons, including crude oil and condensate, fell 6% in April from a year ago to 1.75 millon bpd.

Pemex did not respond to a request for comment.

In its most recent earnings call, officials said they were seeking to mitigate the decline of crude oil production by "reinforcing maintenance" of wells at productive fields and drilling new ones.

Pemex reported steep first-quarter declines at fields including Zaap, Xanab, Ayatsil, Ku and Quesqui.

Natural gas production fell almost 12% year-on-year in April to 4.322 million cubic feet per day, the data showed. (Reporting by Ana Isabel Martinez Editing by Stefanie Eschenbacher and Richard Chang)