(Reuters) -The European Union has struck a tentative deal to launch four Galileo navigation satellites using Falcon 9 rockets of U.S.-based SpaceX, European officials said on Tuesday, in the latest sign of pressure caused by a gap in European launch capacity.

The agreement spans two launches pencilled in for April and July next year, carrying two satellites each, EU Internal Market Commissioner Thierry Breton told reporters in Seville, Spain, following EU ministerial talks on competitivity in space.

The plan is subject to authorisations surrounding the protection of the satellites, which are part of a sensitive European system that includes a secure signal in addition to a public alternative to the U.S. Global Positioning System.

Breton told a news conference the provisional contract with SpaceX was worth 180 million euros ($191.99 million).

Delays in the Ariane 6 launcher, a grounding of the smaller Italian Vega-C following a launch failure in 2022, and the loss of access to Russian Soyuz rockets following the Ukraine conflict have left Europe with a gap in launch capacity.

The 22-nation European Space Agency, which includes most EU states, last year turned to Elon Musk's SpaceX to launch its Euclid space telescope to survey evidence of dark matter and dark energy in the universe. Euclid's first images were due to be released later on Tuesday.

In 2024, the private U.S. company will also launch Europe's scientific Hera probe, a follow-up mission to NASA's DART spacecraft, which last year succeeded in altering the path of a moonlet satellite in the first test of a future planetary defence system.

($1 = 0.9376 euros)

(Reporting by Tim HepherEditing by Mark Potter and Barbara Lewis)