More than 40 marines were killed, an official said, but there were signs the toll could much be higher. At the Mykolaiv morgue, dozens of bodies were laid out in a storage area.
Madrid endorsed a plan for limited autonomy for the territory in northwestern Africa, but the change in policy was denounced by independence groups and could aggravate relations with Algeria.
Ukraine said it had temporarily lost contact with officials in the strategic port city of Mariupol, and a Russian rocket attack on a military site in Mykolaiv left dozens dead.
The United States, Russia and China have all been racing to develop hypersonic weapons, which can maneuver in flight at more than five times the speed of sound.