CARACAS, Venezuela — Venezuelan authorities have arrested two people suspected of plotting to kill Hugo Chavez by blowing up the president’s plane with heavy artillery, the country’s top security official said yesterday.

Justice Minister Tarek El Aissami said the suspects were apprehended Tuesday during a raid on a house in western Zulia state, where authorities found a cannon and four grenades. He said the names of the suspects would not be disclosed for “strategic reasons.”

At least six people, including retired and active military officers, have been detained so far for alleged links to the plot. Military prosecutors are questioning others. None of the suspects has been formally charged.

“What was being planned here was the president’s assassination … a plan with the objective of sowing violence in our country” and stopping the government agenda, Mr. Aissami told Venezuela’s state-run news agency.

Mr. Aissami said the suspects caught in Zulia could have been planning to kill the president by shooting down the presidential jet — a possibility that Mr. Chavez raised when the purported plot was first discovered.

“The cannon we found is for downing planes. It has highly destructive power,” he said.

Mr. Chavez claims that radicals backed by America are plotting to assassinate him. The socialist leader recently ordered the American Ambassador, Patrick Duddy, to leave Venezuela, accusing the envoy of aiding the purported plot.

American officials deny it.

Mr. Chavez made the accusations on September 11, after a recording surfaced of a purported conversation between conspirators discussing plans to assassinate him and topple his government. He claims plotters sought to blow up the presidential plane or bomb the presidential palace.

It was not clear when the conversation broadcast on state television was recorded. The military officers identified as suspects have not responded to the accusations publicly, and some government critics suspect the recording is bogus.

Mr. Aissami suggested that officials in Zulia, which is governed by an opposition leader, Manuel Rosales, could be involved in the alleged conspiracy and chided government foes for dismissing the plot as a ploy to distract attention from domestic problems.

“I don’t think anybody can be so naive to think they had this cannon, which has a range of 700 meters, to kill a deer,” he said.

Mr. Chavez has accused Washington of conspiring with his opponents to assassinate him or spur his ouster dozens of times since he took office in 1999.