KNOXVILLE (AP) — Retail travel center operator Pilot Flying J is buying Western Petroleum LLC, a fuel transportation company.

The purchase price was not announced Thursday in a news release issued by the two companies.

Pilot Flying J, based in Knoxville, has more than 550 retail locations across North America and also delivers fuel to customers in 47 states and eight Canadian provinces. It employs approximately 18,000 and bills itself as the largest operator of travel centers in North America.

Western Petroleum, based in Vernal, Utah, transports fuels and other items. It has 500 employees.

Jimmy Haslam, Pilot Flying J president and CEO, said Western Petroleum has positioned itself for growth in key regions where hydraulic fracturing and hydrocarbon drilling are escalating.