Travel near the Burmese border in the provinces of Chiang Mai, Chiang Rai and Mae Hong Son should be undertaken with caution. The Burmese army shelled the border town of Mae Sai in Chiang Rai province Feb. 11, killing three civilians. Thai forces have been reinforced in the area to counter further incursions, and travelers were urged to avoid several highways, including 1, 1089, 1130, 1234 and 1149, because of military movements. The border area is prone to clashes between Burmese forces and an insurgent army which usually take place in the dry season, November through March.