"There is no information that the visit is still planned," spokesman Dmitry Peskov told The Associated Press. He refused to elaborate, but the comments follow a Russian special services warning of a possible attempt to assassinate Putin during his visit.

Earlier Monday, Peskov said that Putin was still planning on arriving in Tehran on Monday evening after meeting with German Chancellor Angela Merkel in Germany, and the Kremlin's change in tone was a strong indication that the president was likely to cancel his visit.

The move is certain to anger Iranian officials, who denied reports about the assassination plot. Iran's Foreign Ministry earlier Monday insisted Putin was planning on visiting Tehran.

"Mr. Putin will be arriving this evening. ... Putin and other heads of Caspian Sea states will be coming to Tehran to attend the summit," Foreign Ministry spokesman Mohammad Ali Hosseini told reporters.

Hosseini also dismissed reports about a plot to assassinate Putin as disinformation spread by adversaries hoping to spoil Russian-Iranian relations.

"Such kinds of false news won't have any impact on the plans that we have for (Putin's) visit," Hosseini told a press conference Monday.

Russia's Interfax news agency, citing a source in Russia's special services, said Sunday that suicide terrorists had been trained to carry out the assassination.

Putin's visit to Iran, during which he was set to meet with Iranian President Mahmoud Ahmadinejad and attend Tuesday's summit of Caspian Sea countries, would be the first official visit by a Russian head of state to Iran. No Kremlin leader has traveled to Iran since Josef Stalin in 1943, for a wartime summit with Winston Churchill and Franklin D. Roosevelt.

Officials have reported uncovering at least two other plots to kill Putin on foreign trips since he became president in 2000.

Ukrainian security officials said they foiled an attempt to kill Putin during a summit in Yalta in August 2000. And in 2001, Russian security officials said a plot to assassinate Putin earlier that year in Baku, the capital of Azerbaijan, had been uncovered by the Azeri special services.

Russian officials linked both alleged plots to Chechen separatists. Putin had sent troops back into the southern Russian republic to crush resistance to Moscow's rule.

Putin's trip to Iran, if it goes ahead as planned, will be closely watched by U.S. officials, who accuse Iran of trying to produce nuclear weapons. Iran says its nuclear program is peaceful.

Russia has resisted the U.S. push for stronger sanctions against Tehran and strongly warned Washington against using force in its standoff over its nuclear program.