Held in the iron grip

Question

Part of a sentence I am trying to translate from English to Spanish is the following:

...they were held in the iron grip of relentless laws

The machine translator came up with the following:

...se celebraron en el puño de hierro de las leyes implacables.

I changed that to the following:

...fueron agarrados en el puño de hierro de las leyes implacables.

Would this be the best way to say this? Is there a better way to translate this? Thanks in advance for your comments.

Answer 1

Hmmm, I think I have heard 'mano de hierro'....

Answer 2

Estaban detenidos en la mano de hierro/acero de las leyes implacables

Answer 3

I think I have heard 'mano de acero'....