The ministry says six of those killed by gunshots were minors.
It says more than 2,700 people were injured Monday, including 1,360 by live fire. Of the wounded, 130 are in serious or critical condition.
The ministry did not say how the baby was exposed to tear gas.
On Monday, tens of thousands of Palestinians rallied near Israel's border fence to protest a blockade of their territory and the move of the U.S. Embassy to contested Jerusalem that day.
It was the deadliest day in Gaza since a 2014 war between Israel and Gaza's ruling Hamas.
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