They're spreading out in front of what could be the enemy advance.

His father had directed him to leave them in the valley to slow the enemy advance.

As the enemy advances, the small forward element will pull back.

Set up a line of defense there and prevent any further enemy advance.

If a rally is used after a retreat, make it on the high ground to slow the enemy advance.

Arthur joined us and received word of the enemy advance calmly.

To kill him was to slow down the enemy advance.

He was killed almost at once, but his gallant action held up the enemy advance.

His mission was to check the enemy advance in the Merdjayoun area.

A few would remain, keeping a watch for enemy advances.