RIO DE JANEIRO, Sept 24 (Reuters) - The International Organization for Migration (IOM) has formally asked Brazil to receive some Haitianmigrants camped along the U.S.-Mexico border hoping to enter the United States, according to two sources with knowledge of the request. The petition from the IOM, a United Nations agency, comes as U.S. President Joe Biden faces mounting pressure to resolve yet another migration dilemma. Crossings at the U.S.-Mexico border have jumped to their highest levels in 20 years in recent months, sparking political headaches and logistical obstacles for the United States and Mexico. Around 15,000 mostly Haitians were camped just north of the Rio Grande river this month as they attempted to enter the United States, although the numbers have since fallendramatically. Washington has begun flying some back to Haiti, while Mexico has urged others to give up their U.S. dreams and seek asylum in the south of the country. The IOM asked that Brazil receive Haitians who have a Brazilian child, or who have passed through Brazil before entering Mexico on their journey north, the two sources said. They said the first request was more likely to be approved. One of the sources said the second one would require more analysis. Without mentioning the IOM request, Brazil"s foreign ministry said in a statement that "the topic was discussed in conversations between authorities from different countries and is being analyzed in light of current legislation." The IOM, via its Mexico office, said it has "a voluntary return program, assisting migrants of various nationalities, and the implementation of this program requires an agreement among the countries involved." It gave no further details. After Haiti"s 2010 earthquake, many Haitians migrated to Brazil, where they found work and started families. More than 105,000 arrived in Brazil between 2011 and 2018, according to Brazil government data. With Brazil suffering from years of political dysfunction, economic malaise and a brutal coronavirus pandemic, some have since set off for the United States, according to officials and interviews with migrants. U.S. Secretary of State  Antony Blinken  and Brazilian Foreign Minister Carlos Franca discussed the proposal when they met in New York on Tuesday on the sidelines of the UN General Assembly, one source said. Blinken asked Brazil to accept some Haitians who are set to be deported from the United States in the coming weeks, the source said. According to an official readout of their meeting, Blinken and Franca "discussed the cooperation between the United States and  Brazil on bilateral, regional, and global issues." A U.S. State Department spokesperson declined to comment on discussions between Blinken and Franca, or on "the specifics of ongoing diplomatic discussions." The spokesperson directed questions on "commitments" Brazil had made to the IOM to Brasilia. "We are in close communication with other countries in the region to address the challenges of irregular migration," the spokesperson said. One of the sources said one hurdle that would need to be overcome as part of the proposal is which country would pay for the flights to bring the Haitians back to Brazil. The source assumed the United States, which is already sending planes full of people back to Haiti, would pay. In the past the U.S. State Department has funded IOM-organized returns of Central American migrants from Mexico. The current U.S. deportation flights to Haiti have caused controversy. The U.S. special envoy to Haiti Daniel Foote quit over the expulsions, saying in a letter circulating on Thursday that the "collapsed" Caribbean nation was unable to support the returning migrants. Haiti, the poorest country in the Western Hemisphere, has been rocked by the assassination of its president, gang violence and natural disasters in recent months.