Anti-U.S. cleric Moqtada al-Sadr has released a letter calling on his followers in Iraq to demonstrate “in millions” after the Muslim holy month of Ramadan ends next week.

In the letter, released late Friday, Sadr urged his followers to demonstrate against the government of Prime Minister Nouri al-Maliki, saying it has not done enough to improve public services. Many Iraqis do not have full electricity in their homes or sufficient running water.

“We remind the government about the fate of the Arab leaders who were swooped down on by their own people and toppled in Tunisia, Libya and Egypt,” the Shiite cleric wrote.

Sadr also praised the Libyans who brought down Moammar Gaddafi’s regime this week, and he called on his followers to continue to oppose the American troop presence in Iraq.

“The Iraqi people will stand by the Iraqi resistance until it brings down the last U.S. occupation’s flag from Iraq’s land,” he wrote.

Sadr had thrown his support to the Maliki government in a major speech in January that marked his reemergence in Iraq after four years of self-imposed exile.

At that time, he urged his followers to maintain their fierce resistance to the United States but also warned that his movement would begin targeting Iraq’s government if it did not restore services or security and hold to a timeline for a full U.S. military withdrawal by the end of 2011. He gave the government a separate deadline of six months to improve matters; on Friday, it appeared that the government has failed his test.

Sadr, who has millions of followers in the poorer areas of Baghdad and in the country’s south, is believed to have spent at least part of the past four years under the tutelage of hard-line clerics in Iran, studying to be an ayatollah. His father, Grand Ayatollah Mohammed Sadiq Sadr, was assassinated in 1999 by loyalists of Saddam Hussein.

In the spring, he paraded with members of his Mahdi Army through Baghdad’s Shiite slum, Sadr City, to demand that U.S. forces leave Iraq, and recently he created a buzz on the Web by appearing in military garb and draped in the Iraqi flag, attended by a soldier wearing a ski mask. Members of the Mahdi Army’s armed militia, the Promised Day Brigade, have asserted responsibility in recent weeks for more than 16 attacks on U.S. forces in the south.

Elsewhere, activists in Baghdad are using Facebook and other social media to plan a Sept. 9 rally in the capital, also to protest the lack of services and poor security. Dozens of people were killed in February during protests inspired by the Arab Spring, and Maliki’s government has been criticized for rough treatment of many who took to the streets during those days.

Special correspondent Aziz Alwan contributed to this report.