(CNN) -- Police attacked the former Maldives president Wednesday, beating him up a day after he stepped down, the Maldivian Democratic Party said.
"We strongly condemned the violent attack by the Maldivian Police Service on President (Mohamed) Nasheed and senior officials of the MDP," the party said in a written statement. "President Nasheed is being beaten up as of now in an ongoing peaceful protest."
Four members of Parliament were detained as violence gripped the nation's capital, Male, lawmaker Eva Abdulla said, and the head of the party was hospitalized in critical condition.
Police sprayed tear gas and beat demonstrators with batons, she said, and the violence left some protesters bleeding in the streets.
"It's absolute lack of order at the moment," she said. "Nobody seems to be in charge."
Police could not be immediately reached for comment.
Earlier Wednesday, Nasheed had called for his successor to leave office, saying he was forced to resign in a coup.
Nasheed resigned Tuesday after a revolt by police officers. Vice President Mohammed Waheed Hassan was sworn in as president shortly after Nasheed resigned.
Nasheed was the first democratically elected president of the Indian Ocean nation in three decades.
In a nationally televised address, he said he was stepping down because he didn't feel he was able to maintain security and peace in the country, which attracts hundreds of thousands of tourists every year.
"We're urging the government and the political parties to work together to resolve the situation peacefully and we're continuing to monitor the situation," U.S. State Department spokeswoman Victoria Nuland said Wednesday. She said U.S. envoy Robert Blake would make a stop in Male on Saturday as part of previously scheduled trip to the region.
Strategically located in the Indian Ocean but extremely poor, the Maldives is threatened by rising sea levels. Nasheed once held a Cabinet meeting underwater, with ministers wearing scuba gear, to highlight the problem.
CNN's Catherine E. Shoichet contributed to this report.