Буду благодарна за любые идеи.

...protesters joined hands to form human chains ...

как здесь

https://meduza.io/feature/2020/08/13/vy-tochno-videli-etot-snimok-on-stal-odnim-iz-simvolov-protestov-v-belarusi-my-pogovorili-s-ego-avtorom-olgoy-shukaylo-o-samoy-fotografii-i-o-roli-zhenschin-v-belorusskom-proteste

If you use this, it can include both:

* protesters holding hands

and/or

* protesters with (interlocked arms/linked arms)

as it's non-specific.

If you want to be more specific, say either:

'to hold hands to form a human chain'

or

'to link arms to form a human chain'

as appropriate.

OFF: For your amusement, here's an example of protesters in London (almost!) holding hands (but not linking arms) in a very half-hearted attempt to prevent Boris Johnson seeing the Queen: https://www.youtube.com/watch?v=uvXTl0JrGBU

It wasn't a very well-organised protest, was it....?