MEXICO CITY — Hondurans marched in protest Sunday, demanding an impartial count of the results of last week’s presidential election and chanting their opposition to President Juan Orlando Hernández’s bid for a second term.

Huge demonstrations in the capital, Tegucigalpa, and the country’s industrial hub, San Pedro Sula, snaked through the streets with an almost festive air as marchers waved the red flags of the main opposition party, which has denounced what it calls fraud in the vote tally.

Despite the relative calm in big cities, a political crisis has engulfed the country over the contested vote tally by the Honduran electoral commission.

After partial results the night of the election gave the main opposition candidate, Salvador Nasralla, a lead of five points, the commission suspended the count for a day and a half. When it resumed, Mr. Hernández was reported to have steadily gained on Mr. Nasralla and then took a small lead, with almost 95 percent of the polling places counted.