Dozens of armed Yemeni Shi'ite Houthi demonstrators protested in front of the Saudi embassy in Sanaa on Saturday calling for the release of a prominent Shi'ite cleric who was sentenced to death by a Saudi court this week, a Reuters witness said.
The Houthi demonstrators, who were carrying kalashnikov AK-47 rifles, also chanted "Death to America, Death to Israel" slogans.
Yemeni security and military forces blocked both sides of the street in front of the embassy and watched the demonstration.
A Saudi judge sentenced to death on Wednesday Sheikh Nimr al-Nimr who had called for greater rights for the kingdom's Shi'ites.
The Houthis established themselves as Yemen's new powerbrokers last month, capturing the capital Sanaa on Sept. 21 to little resistance from the weak administration of President Abd-Rabbu Mansour Hadi.
Clashes between Houthis, Sunni tribesmen and fighters from al Qaeda, who regard the Houthis as heretics, have since intensified across several provinces in Yemen, alarming neighbouring oil-exporting giant Saudi Arabia.
At least 15 people were killed in heavy fighting between Sunni tribesmen and Houthi rebels in central Yemen on Friday, increasing fears of outright sectarian warfare.