Cruz Beckham‘s online tirade against his big brother Brooklyn and his wife Nicola Peltz came on the heels of Brooklyn and Nicola asking the Beckhams to stop attacking them in the media … TMZ has learned.

Sources with direct knowledge tell TMZ … folks from Brooklyn and Nicola’s camp reached out to David, Victoria, Romeo and Cruz in the past few weeks, asking them to stop talking to Brooklyn and Nicola if they were going to continue leaking negative stories about them.

We’re told Brooklyn and Nicola want to squash the longstanding family feud … but the problem is, they feel no matter what they do, they get attacked in the press and online.

While we’re told Brooklyn and Nicola hoped their message would resonate … it definitely isn’t sticking with Cruz — with Brooklyn’s younger brother seemingly still dragging the couple in a series of recent scathing, since-deleted IG Notes messages.

As we reported … Cruz appeared to pop off on Brooklyn and Nicola, writing … “Ur a d**k now 😢,” “You’re a fraud,” “Instant karma gonna get you,” “People notice,” and “Ur dead to me.”

Other messages from Cruz … “Oh it’s Stockholm syndrome,” “Bloody inbreds,” “Whole family o’ c**ts,” and most recently “How can 2 people make so many ugly c*nts.”