The Trump administration on Sunday accused the European Union of undermining its efforts to isolate authoritarian Venezuelan President Nicolás Maduro, denouncing the bloc’s top diplomat for dispatching a mission to Caracas without consulting with Washington.

The dispute suggested a growing divide across the Atlantic over how to handle Venezuela’s socialist government. The Europeans have tended to see Washington’s hard line position as harsh and ineffective. Washington has viewed Brussels as too willing to deal with Maduro.

“This will make relations with the E.U. bureaucracy more difficult,” Elliott Abrams, the U.S. special representative on Venezuela, told The Washington Post Sunday.

Brussels on Friday confirmed an E.U. mission had arrived in Caracas as part of an effort by the bloc’s foreign policy chief, Josep Borrell, to secure “minimum democratic conditions” for upcoming legislative elections. The U.S.-backed opposition led by Juan Guaidó is boycotting the December vote, which it argues will be manipulated and used by Maduro to consolidate power. The U.S. has also called for a boycott.

The Europeans have said the elections as currently organized would not meet minimum democratic conditions. But they’ve been in talks with Maduro’s government and dissenting members of the opposition on a way forward.

To nudge all sides toward agreement, the E.U. team, led by Enrique Mora, the bloc’s deputy secretary general for political affairs, and Javier Niño Pérez, its leading diplomat on the Americas, met separately with Guaidó and with senior representatives of Maduro’s government over the weekend. They proposed a suspension of the December vote for at least six months, during which time a European negotiating team would try to secure the minimum standards needed to allow E.U. monitors to observe and potentially lend international legitimacy to the vote.

Guaidó said the opposition was informed of the E.U. visit 24 hours before the mission arrived. In a statement to The Post, he maintained his position that “postponing a fraud does not make it less of a fraud.”

The United States and more than 50 other nations consider Maduro illegitimate. They recognize Guaidó as Venezuela’s rightful leader.

Abrams said Borrell devised the E.U. mission without consulting Washington, individual E.U. member nations, the Venezuelan opposition or key Latin American countries.

“It’s not useful to have Borrell’s office working on its own,” Abrams said. “It’s fair to call it cowboy diplomacy.”

Abrams said Borrell, a longtime socialist politician in Spain who became the E.U.’s top diplomat late last year, could be eager to reach a deal with Maduro for domestic political reasons and warned that he might lower the bar for a free and fair vote.

“If the regime agrees to postpone [the election] and does so in a deal with Borrell to get European monitoring, [Borrell] won’t want to fail,” Abrams said. “He will want to succeed, and therefore he will be inclined to accept regime excuses and accept conditions that are unacceptable in a democracy.”

An E.U. spokeswoman said the mission had “nothing to do with Spanish politics.” She said Borrell moved forward after receiving backing from members of the International Contact Group, a cluster that includes Mexico, Uruguay, Costa Rica and some European nations. Individual E.U. member states, the spokeswoman said, were informed of the mission before its departure.

“We believe there is a window of opportunity to support a peaceful and democratic transition in Venezuela,” she said.

A senior member of the opposition, who spoke on the condition of anonymity to discuss sensitive issues, said Guaidó was advised of a possible mission on Wednesday, but was not told it was happening until after the team had left for Venezuela on Thursday.

The Europeans met with Guaidó on Friday before holding two rounds of meetings with senior Maduro officials including former communications minister Jorge Rodríguez, Miranda state governor Hector Rodríguez and foreign minister Jorge Arreaza. E.U. officials told the opposition that Maduro’s side appeared reluctant to postpone the vote, but held out the “tiny” possibility of a delay.

Abrams said U.S. assessments suggest Maduro’s government is divided on whether to postpone a vote. The senior Venezuelan opposition figure said the E.U. should have told the opposition of its mission sooner, but the opposition had “confidence” the Europeans would not seek a deal with Maduro that did not address their five key demands for free elections, among them a new electoral council and permission for all barred opposition politicians to run.

The spat between the E.U. and the United States, the official said, left the Venezuelan opposition in an awkward position.

“I do think that there is a component of the [European] mission that is anti-U.S., but we need the E.U. and we need the U.S.,” the opposition official said. “They should not put us in the position of having to choose. It’s like we are the kids and the parents are fighting.”

Faiola reported from Miami. Ana Vanessa Herrero in Caracas contributed to this report.