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We have analyzed three XMM-Newton observations of the central part of theunidentified TeV \gamma-ray source HESS J1804-216. We focus on two X-raysources 2XMMi J180442.0-214221 (Src 1) and 2XMMi J180432.5-214009 (Src 2),which were suggested to be the possible X-ray counterparts to the TeV source.We discover a 2.93 hr X-ray periodicity from Src 1, with the pulse profileexplained with a self-eclipsing pole in an eclipsing polar. Src 2 exhibits astrong Fe emission line (FWHM ~0.3 keV and equivalent width ~0.8 keV) and largeX-ray variability on timescales of hours and is probably an intermediate polar.Thus Src 1 and Src 2 are probably two field sources not responsible for the TeVemission. The observations were contaminated by strong straylight from a nearbybright source, and we see no clear extended X-ray emission that can beattributed to the supernova remnant G8.7-0.1, a popular possible associationwith the TeV source. The other possible association, the pulsar wind nebulacandidate PSR J1803-2137, shows little long-term variability, compared with aprevious Chandra observation. Many point sources were serendipitously detected,but most of them are probably normal stars. Three new candidate compact objectsystems (other than Src 1, Src 2 and PSR J1803-2137) are also found. They arefar away from the TeV source and are probably also magnetic cataclysmicvariables, thus unlikely to be responsible for the TeV emission.

XMM-Newton Observations of the TeV \gamma-ray Source HESS J1804-216