A group of 16 congressional Democrats asked President Barack Obama in a letter Friday not to impose more sanctions against Venezuela’s top leaders after an initial wave of penalties were announced last March. The letter’s signers said the sanctions could undermine the United States’ diplomatic efforts in the Americas and have a negative impact on the very Venezuelan opposition elements they were meant to protect.

“Beyond negative impacts on regional cooperation, the sanctions may actually hinder human rights and dialogue inside Venezuela. While the apparent rationale for the sanctions was to help protect the human rights of opposition protesters, the Venezuelan people overwhelmingly oppose these same sanctions, and Venezuelan human rights groups fear they will exacerbate domestic tensions,” the letter said, according to the Huffington Post.

The Democrats offered praise for Obama’s efforts to restore diplomatic connections with Cuba and urged the president to use similar methods to engage Venezuela’s leaders. “We instead urge you to continue your admirable efforts to engage in direct dialogue with the Government of Venezuela and work with other countries and regional multilateral organizations to foster dialogue and democracy in Venezuela and throughout the hemisphere,” the letter added.

Obama’s executive action in March against seven top Venezuelan officials included asset freezes and international travel restrictions. The Obama administration formally identified Venezuela as a national security threat and accused government officials of committing human rights violations and targeting opposition protests.

“Venezuelan officials past and present who violate the human rights of Venezuelan citizens and engage in acts of public corruption will not be welcome here, and we now have the tools to block their assets and their use of U.S. financial systems,” the White House said in a March statement, according to Reuters.

A top U.S. State Department official traveled to Venezuela’s capital city of Caracas earlier this week to meet with the government of President Nicolas Maduro. U.S. and Venezuelan officials have engaged in on-and-off diplomatic talks since April.