Oil prices held near $100 a barrel Wednesday amid investor concern that the unrest in Libya could spread across the Middle East. The benchmark U.S. oil contract, West Texas Intermediate, was up 39 cents to $100.02 a barrel for April delivery.

Brent crude, the main oil contract in Europe and other parts of the world, was up 18 cents to $115.60 a barrel.

Oil prices eased somewhat earlier this week, falling back from record highs hit during last week’s volatile trading. But the U.S. benchmark price rose back above $100 early Wednesday amid renewed geopolitical concerns.

The recent run-up comes amid fighting between rebels and forces loyal to Libyan leader Moammar Gadhafi.

But investors are also nervously watching developments in Iran, the fourth largest crude exporter worldwide, following reports Tuesday of sporadic protests and clashes with security forces on the streets of the capital, Tehran.

In addition, antigovernment movements have roiled Yemen, Oman, Bahrain and other nations in the region after protesters in Egypt and Tunisia pushed out unpopular leaders earlier this year.

While Saudi Arabia and other members of the Organization of the Petroleum Exporting Countries have pledged to increase production, many investors are concerned that unrest in a region that controls much of the world’s oil reserves could result in supply disruptions.

“The underlying fear is still that the current unrest will — or has already started to — spread to other countries,“ according to a research report from Cameron Hanover, a firm that specializes in energy price risk management.

However, the amount of oil that has been taken off the world market so far has been relatively minimal. Analysts say global crude supplies remain relatively flush.

The U.S. government’s weekly oil inventory report is due later Wednesday.

Meanwhile, prices for gasoline continued to follow oil prices higher. The national average price for a gallon of regular gasoline rose 1.2 cents to $3.387 on Wednesday, according to a daily survey from AAA.