pick up/ pick off/ nail down

Dear teachers,

Would you be kind enough to tell me whether I am right with my interpretation of the expression in bold in the following sentences?

Small bands of elite American Special Operations forces have been operating with increased intensity for several weeks in Kandahar, southern Afghanistan’s largest city, picking up or picking off insurgent leaders to weaken the Taliban in advance of major operations, senior administration and military officials say.

pick up = take into custody; apprehend

pick off = take off = shoot death

The chancellor predicted that it would be only a "matter of days" before a rescue package for Greece was nailed down.

nail down = establish conclusively

Thank you for your efforts.

Regards,

V.

Your interpretations are correct.