Unity Party's assistant secretary-general for press and public affairs, Mohammed Ali, said Sirleaf was expelled for violating the party's constitution. He said Sirleaf is accused of sending people to campaign against the party.
Vice President Joseph Boakai, who served as Sirleaf's deputy for 12 years, lost the Dec. 26 runoff elections to former international soccer star George Weah.
Ali added that the president was also seen campaigning with Weah. He said Boakai supports the decision to expel Sirleaf Johnson.
Sirleaf's press secretary Jerolinmek Piah and Information Minister Eugene Nagbe told The Associated Press late Saturday the president will react later.
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