CARACAS, Jan. 30 (Xinhua) -- Venezuelan President Nicolas Maduro said Friday that U.S. agencies are plotting to overthrow him, and asked President Barack Obama if he is aware of the conspiracy.

In a speech from the presidential palace, Maduro said that several agencies of Obama's government have "various conspiracy plans on Venezuela" and are plotting a coup against him.

"President Obama, are you aware of these plans to promote violence and a coup in Venezuela? I appeal to your conscience," said Maduro.

A time may come when it's impossible to maintain diplomatic relations with the United States because of constant attacks from both Washington and American diplomats on Caracas, said the president.

"There are U.S. diplomats in Venezuela contacting military officials to betray their country, looking to buy socialist political leaders, public opinion leaders and entrepreneurs to provoke a coup," he said.

Maduro appreciated governments from Latin America and the Caribbean for their support during the recent summit of the Community of Latin American and Caribbean States in Costa Rica, where they condemned the sanctions imposed by Washington on Caracas.