Argentina's President Cristina Kirchner met with the head of US oil and gas giant ExxonMobil to discuss investments in her country, Argentine officials said in a statement. Kirchner and Miguel Galuccio, the head of recently nationalized Argentine oil firm YPF, spoke to ExxonMobil CEO Rex Tillerson about unconventional hydrocarbon development in Argentina, YPF said in a statement. "Unconventional" refers to the complex methods used to harvest hard-to-reach oil and gas deposits, such as fracking, which involves shattering source rock in order to release reserves. At the meeting requested by Tillerson at a Manhattan hotel, the officials discussed ways for YPF and ExxonMobil to accelerate their plans to develop the unconventional resources. YPF described the meeting as "very positive," while a spokesperson told AFP that ExxonMobil would have no comment. Galuccio, 44, who worked at oilfield services giant Schlumberger before accepting his new post in May, also met with banks and investment funds, YPF officials told AFP, and on Friday is scheduled to meet with other businessmen. Argentina is keen to develop the 30,000 square kilometer (12,000 square mile) Vaca Muerta (Dead Cow) reserve, located in Neuquen province, in Argentina's southern Patagonia region. Argentina has the world's third-largest shale-based, unconventional hydrocarbon resources, after the United States and China, according to Galuccio. In May, the Argentine government seized YPF from Repsol, accusing the Spanish oil giant of allowing oil and gas production to lapse and forcing Argentina's oil import bill to rise. YPF produces 34 percent of the oil and 25 percent of the natural gas in Argentina, according to industry figures. The company aims to invest $37.2 billion between 2013 and 2017 so that Argentina can obtain long term energy self-sufficiency. Earlier this month YPF signed a memorandum of understanding with US energy giant Chevron to explore and develop shale oil and gas in Vaca Muerta.