Despite a brief halt to the fighting, the security situation in Yemen is too volatile to return to production, Austrian energy company OMV said.

U.S. Secretary of State John Kerry this week expressed support for a three-day halt to the fighting in Yemen. All warring factions in the country agreed to a proposal offered by a Saudi-led collation and the United Nations to halt fighting as of Wednesday.

"We ask the parties to take all steps necessary to advance the implementation of this cessation, call on them to sustain it, and strongly encourage its unconditional renewal," Kerry said in a statement earlier this week.

A military spokesman told state news agency Saba that, as of Thursday, the truce held, though Yemeni forces were ready to respond to any aggression.

Austrian energy company OMV, a player in Yemeni energy, said early this year a production rebound was possible should the national security situation clear. A spokesperson told UPI the situation there was still uncertain.

"Due to the security situation, OMV has currently no production in Yemen," the spokesperson said Thursday.

Apart from production, Yemeni conflict has presented a concern to international oil shipments because of security risks at the country's port terminals. The Bab el-Mandab shipping channel creates unique risks. Threats to the waterway, through which more than 3 million barrels of oil passes per day, means shippers would have to go around the southern tip of Africa.

Yemen has been mired in some form of civil conflict since at least the Arab Spring uprisings that began in 2010. Its president, Abdrabbuh Mansour Hadi, remains in exile.