ALGIERS, (Reuters) – Libya’s Foreign Ministry on Wednesday summoned the U.S. envoy and warned ties will suffer if Washington does not apologise for a U.S. official’s comments about Libya, the state news agency said.

The Libyan Foreign Ministry demanded an apology over what it said were erroneous comments on Libya by a State Department official, “saying if no measure is taken, that would have a negative impact on political and economic relations between the two countries,” Jana news agency reported.

The report did not say what comments the U.S. official had made, but said they were about a speech Libyan leader Muammar Gaddafi made last week in the city of Benghazi when he called for a “jihad” or armed struggle against Switzerland.

U.S. energy companies including Exxon Mobil, Occidental and Hess have invested heavily in Libya, home to Africa’s largest proven oil reservers, since the country emerged from decades of international isolation.

Underlining the growing business ties, the first official U.S. trade mission to Libya in years visited Tripoli last month. The delegation included executives from major U.S. companies keen to enter the Libyan market.

Libya is involved in a fierce diplomatic row with Switzerland which broke out in July 2008 when police in Geneva arrested one of Gaddafi’s sons on charges — which were later dropped — of mistreating two domestic employees.

The dispute dragged in most European countries last month after Libya stopped issuing visas to citizens from the Schengen passport-free travel zone in retaliation for Swiss restrictions on giving visas to senior Libyans.