Mark Zuckerberg just took a veiled shot at Donald Trump

Facebook CEO Mark Zuckerberg is hosting a big tech conference in San Francisco.

And right out of the gate, Zuckerberg stepped on stage and threw a jab at Republican front runner, Donald Trump.

"I hear fearful voices calling for building walls. It takes courage to choose hope over fear," he said. "Instead of building walls, we can build bridges."

That's a reference to how Trump has been calling for a giant wall to be built along the southern US border with Mexico.

Trump wants the wall as a way to stop illegal immigration. He's also been saying that he wants Mexico to foot the estimated $8 billion bill, by the way.

Zuckerberg added, "Our lives are connected. Whether we're welcoming a refugee fleeing war or an immigrant seeking new opportuity. Whether we're coming together to fight global diseases like Ebola or to fight climate change, we have the courage to see that the path forward is to bring people together, not push people apart."

Zuckerberg isn't afraid of getting political. In December, when he and his wife announced the birth of their daughter, they also announced they would be giving away the bulk of their wealth to charity. They plan to support projects that fight disease, improve education and build "strong communities." They will do this through a combination of charitable donations, private investment and promotion of government-policy reform.