SANAA, Yemen — A day after taking power, [filtered word]e rebels in Yemen found themselves increasingly under pressure Saturday as thousands protested against their rule and a group of nearby countries denounced their “coup.” The leader of the Houthi rebels, Abdel-Malak al-Houthi, gave an impassioned speech defending dissolving Yemen’s parliament Friday as the only response to a power “vacuum” — one his group created by besieging the country’s president, who later resigned. The ongoing unrest in the Arab world’s poorest country could benefit Yemen’s al-Qaida branch, considered by America as the world’s most dangerous wing of the terror group.