New York's main contract, light sweet crude for delivery in December, struck 87.49 dollars a barrel -- the highest point since late 2008.
It later pulled back to stand at 86.58 dollars, down 27 cents compared with Friday's close.
In London, Brent North Sea crude for December fell 36 cents to 87.75 dollars a barrel. Analysts said prices were still profiting from strong US employment figures.
"Better-than-expected US labour market data have created optimism among financial investors and this could revive the demand for oil in the US, the world's largest oil consumer," said Commerzbank analyst Carsten Fritsch.