The magnetometer carried aboard the Mars Global Surveyor (MGS) has recently found evidence for strong crustal magnetization in certain regions of Mars, exceeding 1600 nT field strength at about 100 km altitude. In this paper we show that the plasma instruments carried on board of the Phobos 2 spacecraft detected a plasma population between 18:48 and 18:56 UT on 1 February 1989, in the 1000 to 2000 km altitude region, that was very likely strongly influenced by crustal magnetism. It is a plausible interpretation that local magnetic features trapped the observed charged particles. ¿ 2000 American Geophysical Union