Guyana's President Irfaan Ali was sworn in for a second term on Sunday after officially being declared winner of last week's elections, as the small South American country reaps a windfall from offshore oil and gas production.

The country's electoral commission certified Ali's win on Saturday, saying that he had “secured a resounding victory” and that his People's Progressive Party had secured a majority in Parliament, with 36 of the 65 seats.

Guyana, wedged between Brazil, Venezuela and Suriname, has drawn increasing international attention in recent years for its vast oil reserves and mineral wealth. The resource-rich Essequibo region — administered by Guyana but claimed by Venezuela — remains a point of tension.

Ali has won praise for channelling some of Guyana's new oil wealth into popular social programmes.

In a speech after being sworn in on Sunday, the 45-year-old urban planner sent a message of unity. He promised new development that would rapidly expand the economy and said he would continue social programs that “build more prosperity in every family and every home.”

Ali has overseen multiple construction projects, including hospitals and highways, since the discovery of major oil deposits off Guyana’s coast a decade ago. His administration expects to start offering free college tuition this month. He also has pledged to increase the monthly minimum wage, more than double pensions to $500 for people 65 and older and cut power bills in half by next year.

Ali faced off against a 38-year-old wealthy businessman, Azruddin Mohamed, who has been sanctioned along with his father and their gold-exporting company by the U.S. Treasury Department “for their roles in public corruption."

On Sunday, the U.S. State Department congratulated Ali, writing in a statement that it looked forward to working with Ali's government "to advance our shared foreign policy priorities, including strengthening energy security and supporting Guyana’s sovereignty and territorial integrity, particularly with respect to the Essequibo region.”