Ken Livingstone has received some American backing in his row with US embassy staff who refuse to pay the congestion charge.
The mayor was angered by staff's refusal to pay the charge
A New York Times editorial said the mayor was within his rights to demand payment of the £8-a-day charge to drive into central London.
His attack on US ambassador Robert Tuttle led his rivals to criticise his "off hand and irrational remarks".
The US embassy said it is exempt from the charge under the Vienna Convention.
But the mayor said the convention protects diplomats against taxes while the congestion charge is a charge for a service.
In an editorial published on Friday, the New York Times agreed.
"The British make a good case that the charge is not a tax, but a toll for the use of selected streets. Their diplomats, they note, regularly pay tolls on American roads and bridges," the editorial said.
It points out that New York Mayor Michael Bloomberg had threatened to tow away the cars of UN diplomats who had not paid their parking fines.
Last week Mr Livingstone was again referred to the Standards Board for England for comments he made about Mr Tuttle.
He is also appealing against a suspension from office for likening a Jewish reporter, who he accused of "door stepping" him, to a concentration camp guard.
The New York Times said: "Mr Livingstone is certainly within his rights to demand payment, which may now amount to hundreds of thousands of dollars."
The mayor's political rivals have accused his outburst and suggested he was increasingly making gaffes that are causing offence.
But Labour London Assembly member Murad Qureshi said it suggested the US public were "with the mayor on this matter".