Come to me and destroy these alien intruders.

The mighty Imperium had given the alien intruders a short break in which to catch their breath.

No alien intruder could penetrate this gigantic underground industrial empire without being seen or detected.

In Engineering, he soon notices alien intruders, who appear to be interfering with the ship's systems.

"Inform them that we are moving in to contact the alien intruder."

"We have caught up with the alien intruder," the captain answered.

The presence of alien intruders will not be tolerated.

It is a political vision that looks beyond the occupation of Kuwait to the region's perennial battle against alien intruders.

They discover one of several alien intruders aboard Voyager and are able to capture one.

That stuff about 'with only one alien intruder, our armed forces will suffice to protect the nation under any foreseeable eventuality' made me laugh.