The average cost of diesel has posted its biggest increase since near mid-February and is around a five-month high, according to the U.S. Energy Department.

It increased 6.8 cents this week to $3.981 per gallon, marking the third straight weekly hike and putting it at its highest level since early April. Despite the increase, diesel is 14.6 cents per gallon cheaper than the same week a year ago.

Prices range from a low of $3.897 in the Gulf Coast region, up 6.8 cents over last week, to a high of $4.128 in the West Coast region, an increase of 5.6 cents during the same time period.

The biggest price increase was seen in the Midwest region, gaining 8.3 cents, for an average of $3.967 per gallon, while the smallest gain was seen in the Rocky Mountain states, adding 1 cent, for an average of $3.937.

Gasoline also increased over last week, with the average U.S. cost picking up 5.6 cents, for $3.608. Even though gasoline has increased for two straight weeks, it remains 23.5 cents per gallon cheaper than the same time a year ago.

All regions of the country reported an increase from last week, with costs raging between $3.406 in the Gulf Coast states, up 2.4 cents, to as much as $3.756 in New England, an increase of 2.7 cents over the past week. The West Coast was close behind at $3.75.

The gain comes as little surprise with oil hitting a more than two-year high last week in New York trading on indications the United State was ramping up efforts for military action against Syria following claims from the Obama administration that the country has killed more than a thousand civilians using chemical weapons. Over the weekend President Obama said he would take his case for action to Congress for a vote.

On Tuesday oil in New York trading gained 89 cents for the day, setting at $108.54 per barrel, which is nearly two and half dollars higher than the closing price a week ago, but off from a peak when it closed at $110.10 last Wednesday.

Although Syria is not a major oil producer in the Middle East, many other countries in the area are, and there are concerns military action could lead to a wider conflict, possibly interrupting oil production, including the U.S.