The sentences below have something in common. Can you determine what it is?

1. I agree certain changes must be made.
2. Try to find one Siamese cat.
3. That's the best pajama I can buy.
4. Nutritionists love niacin.
5. The government insists on formal divestiture.
6. Will people ban only assault rifles?
7. That's real geriatric medicine.
8. Find a co-star I can work with.
9. Marty is a drug and alcohol agent.
10. Did that skycap ever demand money?

First answer: 
Each sentence conceals a related word.

Second answer:
Hidden in each sentence is the name of a country:

1. I aGREE CErtain.................
2. ..........fIND ONE SIAmes cat
3. ..........best paJAMA I CAn buy
4. NutritionistS LOVE NIAcin.
5. .........on forMAL DIVEStiture
6. .........peopLE BAN ONly.........
7. .........reAL GERIAtric medicine
8. .........a CO-STAR I CAn work with
9. .........is a drUG AND Alcohol agent
10. .......skyCAP EVER DEmand money

Credit:
Will Shortz
The Puzzlemaster Presents Vol. 2
UNITED NATIONS