Defying forceful demands for his resignation, Representative Anthony D. Weiner of New York said on Saturday that he was entering a psychological treatment center and seeking a leave of absence from the House to deal with a pattern of reckless online behavior with women.
The House minority leader Nancy Pelosi, shown in a photograph last month, called for the resignation of Representative Anthony D. Weiner on Saturday.
The announcement came as three top Democratic leaders declared that Mr. Weiner, 46, once a rising star in the party, needed counseling and should step down from Congress.
Pressure on Mr. Weiner to leave the House, and spare the Democratic Party from an increasingly embarrassing scandal, had been building all week, but intensified on Friday, after it was revealed that Mr. Weiner had traded private messages with a 17-year-old girl in Delaware.
Mr. Weiner, who friends say has become distraught and fragile in recent days, will use the leave to think about his future and whether to leave Congress, a possibility he has not entirely ruled out, a person close to him said.
But Mr. Weiner’s plan did not satisfy exasperated Democratic leaders, who have been trying to persuade him that he is damaging himself, his family and his party by remaining a member of the House.
Ms. Pelosi spoke to Mr. Weiner on the phone Saturday morning and, notably, released her statement calling for his resignation after he told her of his plan to get treatment and to take the leave.
Mr. Weiner has been talking with a therapist in New York City over the past couple of days, as fallout from his online scandal worsened and he absorbed the message from his colleagues and advisers that his conduct reflected not just bad judgment but perhaps a deeper psychological problem.
“Congressman Weiner departed this morning to seek professional treatment to focus on becoming a better husband and healthier person,” said his spokeswoman, Risa Heller. “In light of that, he will request a short leave of absence from the House of Representatives so that he can get evaluated and map out a course of treatment to make himself well.”
Ms. Heller would not identify the facility or the precise kind of counseling Mr. Weiner, who has admitted having explicit communications with six women he met online, would receive. She stressed that he was carefully considering the calls from his fellow lawmakers urging him to give up his seat.
Mr. Weiner has been resistant in telephone calls over the past week with Ms. Pelosi and Representative Steve J. Israel, chairman of the Democratic Congressional Campaign Committee, who have been pushing him to quit and warning him that, if he does not, they will make their case publicly.
They were especially frustrated, according to one high-ranking Democratic official, when Mr. Weiner repeatedly told them he could not resign now because his wife, Huma Abedin, was traveling abroad with her boss, Secretary of State Hillary Rodham Clinton — an assertion they viewed as an unpersuasive pretext.
Ms. Pelosi had hoped that the congressman would reach the decision on his own to go. In addition to her concerns about the political distraction Mr. Weiner had become, Ms. Pelosi concluded that his behavior required medical intervention.
“When you are this self-destructive, there is obviously something deeper going on with you,” said a Pelosi adviser who spoke on condition of anonymity for fear of being seen as betraying her confidence.
The pressure from colleagues had been building throughout the week, but the report on Friday that Mr. Weiner corresponded on Twitter with a 17-year-old girl further inflamed the situation. A Democratic National Committee official told members of Mr. Weiner’s staff that the congressman’s assertion that his exchanges with the girl, a high school junior, were “neither explicit nor indecent” did not really matter at this point.
The concerns of Democratic leaders were echoed by those closely advising Mr. Weiner throughout the week, who said they watched him become more anguished as sensational news media coverage continued about his graphic interactions with the women on social media.
One friend said it had become abundantly clear that Mr. Weiner was no longer in a position to make clear-headed decisions about his career and health.
“He was falling apart,” said a longtime friend, who spoke on condition of anonymity to protect the relationship.