BEIRUT, Lebanon — Syria’s uprising has become more violent in the country’s most restive regions, in what may signal the start of a protracted armed struggle after six months of largely peaceful protests in the face of a ferocious government crackdown, diplomats, activists and officials say.

Reports have mounted of clashes in Homs; in the outskirts of the capital, Damascus; in the southern Houran region; and at the border near Turkey. Officials and diplomats have spoken of at least three ambushes of military vehicles — two buses and a jeep — in Homs, in which at least five soldiers were killed. Activists have reported other clashes between soldiers and deserters in several regions of Syria.

Though the degree of violence remains unclear, the changing dynamics underline what has become a reality of Syria’s tense stalemate: The longer President Bashar al-Assad remains in power, the more violent the country will become, even if no one knows what will follow him if he is ousted from power. Propelled by frustration, the opposition’s resorting to arms would probably serve the interests of the government, adding validity to its otherwise specious contention that it faces an armed insurgency financed from abroad and driven by the most militant Islamists.

“It is quite simply a trap that the protesters will fall in,” said Peter Harling, an analyst for the International Crisis Group who travels to Syria often.