A United States senator has expressed concern that Venezuelan President Nicolás Maduro is trying to obstruct the actions of the South American country's newly elected National Assembly.

In an open letter addressed to Barack Obama on Monday, New Jersey Senator Robert Menendez urged the president to lead actions to enforce stronger international penalties and monitoring.

"I write to urge you and your administration to take immediate steps to ensure that Mr. Maduro's regime is denied the space to obstruct Venezuela's path to democratic order," Menendez wrote. "I believe you can accomplish this with a combination of close monitoring of key international organizations and meaningful, internationally imposed penalties."

The Obama administration accused the Venezuelan government of interfering with the newly elected congress after Venezuela's Supreme Court blocked a number of elected officials from taking their seats, McClatchy DC reported. However, the administration hesitated to impose greater penalties proposed by Menendez and Miami Rep. Ileana Ros-Lehtinen.

"We are concerned by the Venezuelan government's efforts to interfere with the newly elected National Assembly exercising its constitutionally mandated duties," State Department spokesman John Kirby said on Monday, as quoted in McClatchy DC's report. "We continue to call for respect for the will of the people."

Venezuela's opposition labeled the high court's decision a "judicial coup" after judges blocked four elected lawmakers from taking their seats on Tuesday. The Supreme Court denied the accusations in a statement, stressing out that the allegations "do not contribute to the environment of tranquility and peace," the news outlet further reported.

U.S. Congress officials urged the Obama administration and regional allies to condemn Maduro's government and prevent it from further knocking Venezuela off balance and weakening the National Assembly, McCarthy DC wrote.

"Maduro is up to his dirty tricks only to hold on to power, but we must remain vigilant and apply stringent sanctions to anyone in Maduro's regime who commits human rights violations," Ros-Lehtinen said, as quoted by McCarthy DC.

The Venezuelan president, however, responded to the U.S.' allegations by saying that his country would "not accept imperialism," Euronews reported.

"Why does the State Department and the U.S. government care about the installation of the National Assembly?" Maduro remarked during a television address on Monday evening, as quoted by Euronews.

On Sunday, Venezuela's opposition coalition chose Henry Ramos, who is the 72-year-old secretary of the Democratic Action Party, to be the leader of the new National Assembly, the news outlet noted. The new congress will probably begin with conflicts on Tuesday when it formally selects the branch's president.