* Brent prices jump, volume spikes before 12:00 p.m. EST
* China manufacturing PMI at 18-month high
* U.S. manufacturing expanded at fastest pace in 2-1/2 years
NEW YORK, Dec 2 (Reuters) - Brent crude jumped by more than $2 a barrel on Monday in reaction to strong manufacturing data from both China and the United States and extended gains on rumors of some Russian cancellations.
Volume surged and prices rose nearly $1 just before noon EST (1700 GMT), with several market players citing rumors that cargoes of Russian Urals crude had been canceled in December.
Brent crude for January traded up $2.14 to $111.83 a barrel by 12:19 p.m. EST (1719 GMT). U.S. crude rose $1.10 to $93.82 a barrel.
The February Brent contract also rose by over $2. Refined products gained as well, with RBOB gasoline futures up by 0.044 cents, or 1.66 percent, to $2.7072.
Crude had been trading higher following data showing the U.S. manufacturing sector expanded last month at its fastest pace in 2-1/2 years, outstripping forecasts, and the employment picture also improved.
In China, the official Purchasing Managers' Index showed manufacturing growth at an 18-month high in November due to robust domestic and foreign demand.
A similar indicator for Britain and Germany also showed a pick-up in manufacturing activity.