Yes, if your trips were for business purpose, you can use the U.S Dept of State per diem rates. You may already have this website, click here for US Dept of State Foreign
per diem rates
To read more about Travel expense rules, click here: Publication 463 (2017), Travel, Entertainment, Gift, and Car Expenses "You can deduct all your travel expenses of getting to and from your business destination if your trip is entirely for business or considered entirely for business." Your trip is considered entirely for business if:
You were outside the United States for more than a week, and
You spent less than 25% of the total time you were outside the United States on nonbusiness activities.
For this purpose, count both the day your trip began and the day it ended.
See Pub 463 link above for all details.
To read more click on this link: Publication 463 (2017), Travel, Entertainment, Gift, and Car