On 11 May 1884 French and Chinese negotiators concluded the Tientsin Accord, an agreement designed to end several months of undeclared hostilities between France and China in Tonkin. On 23 June 1884, French troops advancing to occupy Lạng Sơn, in accordance with the terms of this agreement, clashed near the small town of Bắc Lệ with a detachment of the Chinese Guangxi Army. The Chinese opened fire on the advancing French, precipitating a two-day battle in which the French column was seriously mauled.