U.S. on-highway diesel prices are up 2.5 cents from last week, and up 99.3 cents from last year, according to the Department of Energy. The rise to a $3.932 national average follows a slight decline last week that broke a 15-week streak of steady price increases.

The West Coast had the biggest regional price jump, rising over 5 cents to $4.155, making it the most expensive region. The East Coast saw the smallest increase, up $0.014 to $3.952, and Gulf Coast states held the cheapest prices at $3.857.

No region saw prices fall.

The brief and marginal price drop seen last week may return in coming weeks. Oil futures sank Monday as rebels made gains in Libya, raising hopes that the country could resume oil shipments in the near future. Libyan opposition fighters pushed further west toward Sirte, Gadhafi's hometown, after retaking strategic oil infrastructure in Brega and Ras Lanuf over the weekend.

Oil exports from Libya could resume "in less than a week," rebel representative Ali Tarhoni told Agence France-Presse. Tarhoni added that current production of 100,000 to 130,000 barrels a day could "easily" be raised to about 300,000 barrels a day. Before the conflict and Western sanctions cut off Libya's oil exports, the North African nation exported 1.3 million barrels a day of crude.

However, analysts cautioned there's no guarantee that Libyan oil will return to the market anytime soon, despite the reports of rebel progress. The Libyan conflict and the broader unrest in the Arab world has sent crude prices soaring over the last month. New York Mercantile Exchange crude futures hit a recent peak of $106.95 on March 7, the highest level in two and a half years.