FRANKFURT (Reuters) – European satellite launching firm Arianespace said it had called off the launch of two communications satellites seconds before lift-off on Tuesday, citing unspecified problems.

An Ariane 5 heavy-launcher rocket had been due to take off from Europe’s spaceport in French Guiana, carrying satellite Intelsat 37e for Intelsat and BSAT-4a for manufacturer Space Systems Loral.

Arianespace, majority-owned by a joint venture of Airbus and Safran, offers launches with Ariane 5, Soyuz and Vega rockets and says it has sent into orbit more than half of all telecommunications satellites now in service.

The company said engineers were trying to find out what caused the anomaly in the launch, which was to be the fifth Ariane 5 mission from the Guiana Space Center this year.

“During the final seconds of the launch countdown for Arianespace Flight VA239, the checkout process detected an anomaly on the launcher as the Vulcain cryogenic main stage engine was being ignited,” Arianespace said in a statement.

It said it would set a new launch date as soon as possible.