State Duma Speaker Boris Gryzlov backed out of an online interview with Gazeta.ru at the last minute Wednesday, avoiding potentially uncomfortable questions about United Russia and a water filter that he co-patented.

Gazeta.ru said in a statement that the interview, scheduled for Wednesday afternoon, had been postponed indefinitely "in connection with a Security Council meeting that Gryzlov has to attend."

Gryzlov's representatives could not be reached for comment.

The Security Council meeting was announced Tuesday on its official web site. A Security Council statement said the meeting was to focus on measures to combat global warming.

Gryzlov is listed as a permanent member of the council, headed by President Dmitry Medvedev.

In skipping the interview, Gryzlov, a leader of the ruling United Russia party, missed being asked some of the more than 1,100 questions submitted by Gazeta.ru readers over the past five days.

Many of the questions, which were posted online, contained a mixture of angry rhetoric, outspoken criticism of United Russia's policies and sarcasm.

One of the top questions, submitted under the name Sergo, asked: "How is it possible to spend billions on Clean Water and yet pollute the biggest reservoir of clean water, Lake Baikal?"

Clean Water is an ambitious project sponsored by United Russia and engineered by controversial self-styled inventor Viktor Petrik to purify the country's drinking water. Gryzlov and Petrik filed a patent for a water filter in 2007, which they say turns radioactive water into pure drinking water. Prime Minister Vladimir Putin, who leads United Russia, recently approved the reopening of a paper mill that will spew waste into Lake Baikal.

Incidentally, Vyacheslav Khaustov, commander of Moscow's OMON riot police, canceled a similar online interview with GZT.ru late last month after readers submitted abusive comments and critical questions about the police force. Khaustov pulled out at the last moment without explanation.