Argentina's President Fernandez set for cancer surgery
Argentine President Cristina Fernandez de Kirchner is set to undergo surgery for thyroid cancer, with doctors saying she has a good chance of recovery.
Supporters have gathered outside the hospital where she is being treated, carrying signs wishing her well.
After the operation she will rest until 24 January, with Vice President Amado Boudou in charge during her absence.
Ms Fernandez, 58, recently began her second term as president after a landslide election victory.
President Fernandez is being treated at the Austral University Hospital in Pilar, some 60km (40 miles) from the Argentine capital.
People began arriving for a vigil outside the building on Monday and other gatherings are planned, including in the Plaza de Mayo in Buenos Aires and other public squares across the country.
Her office announced last week that cancer - a papillary thyroid carcinoma - was detected on 22 December during routine medical tests.
The cancer had not metastasised or affected her lymph nodes, official said
Specialists say this type of thyroid cancer has a high survival rate if treated early.
Ms Fernandez was re-elected in October by a huge margin and remains extremely popular in Argentina.
During her first term she presided over strong economic growth and implemented a range of social policies to benefit the poor.
The sudden death of her husband Nestor Kirchner in October 2010 brought her a wave of public sympathy.
She began her second term energetically, pushing a number of controversial measures through Congress.
Ms Fernandez is the latest in a series of Latin American leaders to be diagnosed with cancer.
President Hugo Chavez of Venezuela, Paraguayan leader Fernando Lugo, and former Brazilian President Luiz Inacio Lula da Silva have all been operated on in the past year.
Lula was due to begin radiotherapy treatment on Wednesday.
Current Brazilian President Dilma Rousseff was treated for early stage lymphatic cancer in 2009.