KABUL, Afghanistan — In northern Afghanistan, a dispute over billboard portraits of the country’s vice president has inflamed tensions between two of the most powerful regional strongmen, exposing internal political strains even as the government faces a dire challenge from Taliban offensives.

On Tuesday, hundreds of protesters marched in the northern city of Mazar-i-Sharif, the capital of Balkh Province, expressing outrage that photos of Abdul Rashid Dostum, the vice president and a northern Uzbek factional leader, had been removed from two large billboards in the heart of the city.

The demonstrators blamed the province’s governor and Mr. Dostum’s longtime rival, Atta Mohammad Noor, saying that the men who took down the photos were using official police vehicles at a time of tight security for the celebration of the Persian New Year.

Mr. Noor, whose supporters also took to the streets, denied the accusations. Nevertheless, the posturing has raised fears of a return to the kind of open factional hostilities that, at their worst, drove the country’s disastrous civil war in the 1990s. Militias aligned with the two officials continued to intermittently battle each other until 2003, when the United Nations conducted a disarmament campaign and Mr. Noor consolidated his power as governor of Balkh Province and its lucrative resources.