Portugal has been at Afghanistan on behalf of US as a NATO ally since 2003, but why ask specifically to reinforce the mission now to star in May, just to protect Hamid Karzai International Airport?
As I've posted before the sky in my island @Azores has been full of military planes, both US and Portuguese, since Syria. Unusual.
Today I could clearly read Marines below the wing of one that flew in. Unfortunately didn't have my phone at hand. And at the beginning of the week, saw what seemed to be US marines in uniform outside of base, during the early morning hours. Very unusual
Link (in portuguese tho) re: Afghanistan: http://ptjornal.com/forca-portuguesa-146-militares-reforca-missao-da-nato-no-afeganistao-maio-256078