CARACAS, March 31 (Reuters) - President Nicolas Maduro decreed a new annual "anti-imperialist" day on Tuesday and said a signature drive demanding the repeal of U.S. measures against Venezuela had passed 6 million.

In the ideological enemies' worst spat of Maduro's two-year rule, President Barack Obama's government this month declared the OPEC nation a "security threat" and sanctioned seven officials accused of rights abuses and corruption.

Maduro, the 52-year-old socialist successor to Hugo Chavez, said the March 9 measures would from 2016 be commemorated in Venezuela with a new "Day of Bolivarian Anti-Imperialism," a reference to independence hero Simon Bolivar.

"History will remember you, President Obama, as the one who sought to intimidate a people, but instead arose their nationalist, patriotic and Bolivarian spirit," Maduro said in a weekly TV program, from the western city of Coro.

Buoyed by plenty of international support, especially from Latin American neighbors, Maduro is leading a "house-by-house" campaign to obtain 10 million signatures against the measures to take to the upcoming Summit of the Americas in Panama.

Opponents say many Venezuelans are being coerced to sign, especially in state institutions, and decry the move as a waste of time intended to hide the nation's economic crisis and boost the government's popularity ahead of parliamentary elections.