President Barack Obama is deliberately delaying his consent for Venezuela's proposed new ambassador in Washington, the country's embattled leader, Nicolás Maduro, complained on Sunday.

"I have sought diplomatic channels [and] I sent an ambassador, but they still have not given him consent after a year and a half," the Venezuelan president charged on state television, according to Reuters.

"What 'good relations' does the Obama government want if they're not capable of giving consent? What are they waiting for?" Maduro challenged.

Maximilien Sánchez Arveláiz, the diplomat Caracas has proposed as its new ambassador, currently leads Venezuela's mission in Washington as chargé d'affaires, the newswire noted. Sánchez formerly represented his country in Brazil's capital, Brasília, and at the United Nations in New York, according to Últimas Noticias.

Under the Vienna Convention on Diplomatic Relations, ambassadors must be accredited by the receiving nation's head of state. The United States and Venezuela have been without ambassadors ever since Hugo Chávez, Maduro's predecessor, expelled the U.S. envoy in 2008.

The Obama administration and Maduro's government had embarked on what Reuters called a "nascent diplomatic rapprochement" earlier this year, but the process has apparently been hampered by the recent criminal conviction of opposition leader Leopoldo López, who has been sentenced to nearly 14 years in prison on charges of fomenting violence during a 2012 protest.

In the first-ever encounter between the two leaders, Obama and Maduro briefly spoke on the sidelines of the April Summit of the Americas in Panama City, Agence France-Presse recalled. During the summit, the Venezuelan president directly addressed his U.S. counterpart, even though Obama had left the summit room before Maduro spoke.

"I respect you, but I don't trust you, President Obama," Maduro said. "I am willing to talk with President Obama about this issue with respect and sincerity whenever he wants."

Regional leaders from Argentina, Bolivia and Ecuador on that occasion rallied behind Maduro due to widespread irritation over U.S. sanctions against high-ranking Venezuelan government leaders, AFP noted.