Peruvian troops, largely in 40-man platoons, are penetrating an area that has traditionally been controlled by Ecuador.
The farther our troops penetrate the caverns, the more difficult it becomes for us.
In five weeks, Hanoi's troops have penetrated deep into the South.
But the officials say the Ugandan troops never penetrated deeper than about 30 miles and withdrew by late January.
Roman troops, however, penetrated far into the north of modern Scotland several more times.
Israeli troops and bulldozers had penetrated at least 300 yards into Palestinian-controlled territory to clear land as they repaired the fence.
Ungern's troops penetrated deeply into the Russian territory.
On September 11, 1918, these troops rode at night through no man's land and penetrated five miles behind German lines.
This would be the farthest north any uniformed Confederate troops penetrated during the war.
No white troops had ever penetrated to these positions, and they were held as a final rallying point.