The US is seeking United Nations sanctions against the former president and two leaders of the Houthi rebels, accusing them for acting as "spoilers" causing Yemen's latest unrest. All 15 Security Council members must approve sanctions for them to take effect.
Saleh stepped down in 2011 as part of a US-backed, Gulf-brokered deal after months of protests against his rule.
But backers of his successor, Abed Rabbo Mansour Hadi, accuse him of undermining Hadi. Many believe Saleh helped Houthi rebels the past months has they swept into the capital, Sanaa.
The protesters in Sanaa in much smaller numbers than usual today carried posters urging the US ambassador to get out of the country.
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Saleh's party this week accused the American ambassador of telling the former president to leave Yemen by today or face sanctions. Washington vehemently denied making any such demand, but the party's claim has stoked anger of alleged US "interference."
Even some in the Sunni Islamist Islah party a sharp opponent of the Houthis and Saleh joined the anger. In parliament yesterday, a leading Islah lawmaker, Mansour al-Zindani, demanded both the American ambassador and the UN envoy to Yemen leave the country.
The Houthis, who belong to the Zaydi branch of Shia Islam, fought their way out of their stronghold in the north and took control of Sanaa in September, largely by defeating forces loyal of the Islah party.
The past month they have made further gains toward central Yemen, at times fighting al-Qaida's branch in the country.