11.   Russia sent troops into the territory again last September, after Chechnya-based militants invaded the neighboring region of Dagestan.

12.   Russia sent troops into Chechnya again last September after Chechen-based Islamic militants twice invaded the neighboring region of Dagestan.

13.   Russia sent troops into Chechnya in September after Chechen-based Islamic militants twice invaded the neighboring region of Dagestan.

14.   Russian troops entered Chechnya again after Chechen-based militants invaded the neighboring Russian republic of Dagestan last August.

15.   Russian troops entered breakaway Chechnya in September after Chechen-based militants invaded villages in the neighboring Russian region of Dagestan.

16.   Russian troops entered Chechnya in September after militants invaded the neighboring region of Dagestan and were blamed for ensuing apartment bombings elsewhere in Russia.

17.   The campaign began after militants invaded the neighboring republic of Dagestan.

18.   The invasion came after Chechnya-based militants invaded a neighboring Russian region, and after apartment bombings around Russia blamed on rebels.