Last week, the United Arab Emirates seized the Yemeni island of Socotra, sending a force of troops and tanks to the island, expelling Yemeni officials from the seaport and airport. Yemen’s Saudi-backed government-in-exile has now issued a statement complaining the move was “unjustified” and amounted to a violation of Yemeni sovereignty.

This isn’t the first time the UAE, which is involved in the Saudi-led invasion, has acted contrary to the Yemeni force’s interests. The UAE has backed southern separatists in Yemen, and has backed auxiliary forces who seized the Aden airport a few months back.

The UAE Foreign Ministry responded to Yemen’s complaints by angrily accusing Yemen’s PM of “attacking” the UAE with the statement, saying it was “counter to reason” to complain about the UAE taking over the island for “stability” purposes.

Socotra is a strategically important island in a key shipping route. Though the UAE has denied any interest in keeping Yemeni territory, they’ve been known to have ambitions to become a regional power across the Arabian Peninsula and northern Africa, and the island is clearly another step in that direction.