"roll" ,what does this means in the sentence?

Question

Anything that rolled in after August the 6th needs to leave.

"roll" ,what does this means in the sentence?

http://www.voanews.com/english/2008-08-22-voa62.cfm

Answer 1

Troops coming in from Russia.  

Answer 2

Basically, any troops or tanks that went into the combat zone.

Answer 3

Johndroe again called for Russia to return to positions held before the war began. "They had Russian peace keepers in South Ossetia prior to August the 6th. The agreement allows for those Russian peacekeepers to remain in South Ossetia. Anything that rolled in after August the 6th needs to leave," he said.

Basically he is saying that everyone needs to go back to where they were.