Warsaw, Poland - Irena Sendler - credited with saving some 2,500 Jewish children from the Nazi Holocaust by smuggling them out of the Warsaw Ghetto, some of them in baskets - died Monday, her family said. She was 98.

Sendler was a 29-year-old social worker with the city's welfare department when Germany invaded Poland in September 1939, launching World War II. Warsaw's Jews were forced into a walled-off ghetto.
Seeking to save the ghetto's children, Sendler masterminded risky rescue operations. Under the pretext of inspecting sanitary conditions during a typhoid outbreak, she and her assistants ventured inside the ghetto - and smuggled out babies and small children in ambulances and in trams, sometimes wrapped up as packages.

Teenagers escaped by joining teams of workers forced to labor outside the ghetto. They were placed in families, orphanages, hospitals or convents.

Records show that Sendler's team of about 20 people saved nearly 2,500 children from the Warsaw Ghetto between October 1940 and its final liquidation in April 1943, when the Nazis burned the ghetto, shooting the residents or sending them to death camps.

In hopes of one day uniting the children with their families - most of whom perished in the Nazis' death camps, Sendler wrote the children's real names on slips of paper that she kept at home.

When German police came to arrest her in 1943, an assistant managed to hide the slips, which Sendler later buried in a jar under an apple tree in an associate's yard. Some 2,500 names were recorded.

Anyone caught helping Jews in Nazi-occupied Poland risked being summarily shot, along with family members - a fate Sendler only barely escaped herself after the 1943 raid by the Gestapo. The Nazis took her to the notorious Pawiak prison, which few people left alive. Gestapo agents tortured her repeatedly, leaving Sendler with scars on her body - but she refused to betray her team. Zegota, an underground organization helping Jews, paid a bribe to German guards to free her from the prison. Under a different name, she continued her work.

After World War II, Sendler continued to assist some of the children she rescued.

Irena Sendler was nominated for the 2007 Nobel Peace Prize, but did not win. The winner was Al Gore who narrated a slide show.