The three people inside the “pro-regime” tank were killed by an MQ-9 Reaper drone on 10 February – but the incident has only just been confirmed.
No US or allied troops were hurt.
The T-72 tank came from the “same location and same hostile force” which attacked US special operations troops and allied Syrian fighters last week near Deir ez Zor, said a statement.
The tank had been “manoeuvring with coordinated indirect fire on a defensive position occupied by Syrian Democratic Forces and Coalition advisers”, US Central Command added.
SDF fighters and coalition advisers are battling Islamic State militants east of the Euphrates River in Syria.
The Syrian army, which is supported by Iranian-backed militias and Russian forces, are active on the other side of the river by the city of Deir ez Zor.
The strike on the tank happened on the same day that an Iranian drone was shot down over Israel.
An Israeli fighter jet subsequently crashed after being shot down during airstrikes against “Iranian targets” in Syria.
The UN, meanwhile, is pushing to get a ceasefire in Syria.
Its deputy regional humanitarian coordinator for the Syria crisis, Ramesh Rajasingham, said such an idea was “not pie in the sky”.
“What we would like to see is an immediate ceasefire, and I think that’s very possible, we’ve had it before,” he said.
Mr Rajasingham said Eastern Ghouta was at breaking point, and the northwestern Idlib governorate a catastrophe.
In another development, Islamic State has reportedly been ousted from Idlib province.
A spokesman for the Jaish al-Nasr faction said: “We hit them with artillery in the town of Al-Khowein until they agreed to surrender.”
More than 340,000 people have been killed and millions displaced since the conflict in Syria erupted in March 2011.