The U.S. early Thursday carried out a "self-defense" strike, targeting and destroying multiple projectiles that Houthi militants in Yemen were preparing to launch at commercial ships, a U.S. official tells Fox News. 

The strike marks the 12th time the U.S. has conducted strikes against the Houthis in Yemen since January 11th, and the second in under 24 hours. 

The U.K. was not involved in this strike, and it was carried out unilaterally by the U.S. 

It is not related to Sunday's drone attack that killed three U.S. soldiers and injured more than 40 others at a base in Jordan. 

This is a developing story. Check back for updates.