Putin’s plane touched down at Frankfurt airport more than two hours behind schedule after its departure was delayed by snow in Moscow.
The announcement of the delay was made after the Kremlin said Putin had been informed of reports of a possible attempt on his life in Iran, where he is scheduled to travel to from Germany on Monday night.
Russia’s Interfax news agency, citing a source in the special services, reported that a group of suicide bombers would try to kill Putin during a visit to Tehran on Tuesday.
A Kremlin spokesman said: “We cannot comment on this information but we confirm that the president has been informed.”
Iran dismissed the reports as “completely without foundation.”
Putin was tight-lipped about the reports as he arrived at a restaurant near the spa city of Wiesbaden on the banks of the Rhine to dine with the chancellor. He presented Merkel with a large bunch of flowers and they greeted each other warmly.
Their formal talks on Monday are expected to focus on the growing mistrust between Moscow and Washington over US plans to locate an anti-missile shield in eastern Europe, the future status of Kosovo and Iran’s nuclear ambitions.
The meeting was taking place after top US and Russian officials failed to reach agreement on the vexed issue of missile defence in talks in Moscow.
US Secretary of State Condoleezza Rice on Friday rejected a Russian call to freeze plans to place 10 US interceptor missiles in Poland and a targeting radar in the Czech Republic.
Her Russian counterpart Sergei Lavrov responded that his country would “take measures to neutralise that threat” if Washington went ahead with its plans without taking into account Moscow’s concerns.
Washington insists the missile shield is a response to the potential danger posed by nations like Iran, but Moscow fears it will be used against its missiles.
In response, Russia is threatening to tear up the Conventional Forces in Europe (CFE) treaty which sets limits on troops, tanks and other military hardware across the continent, and another key accord, the Intermediate-range Nuclear Forces (INF), which led to the destruction of US and Russian missiles that threatened Europe.
Merkel, who has cultivated close links to Washington, wants to avoid European division over the missile shield issue and has insisted that NATO should be consulted about the plans.
In her weekly video address about Putin’s visit, the German leader said: “We can discuss our differences of opinion openly, but we can also find points we have in common.”
Kosovo is a contentious issue, with Russia strongly opposing Western support for autonomy for the ethnic Albanian-majority province of Serbia.
Pristina has threatened to declare independence unilaterally unless a solution is found in time to meet a December 10 deadline.
Putin shows no sign of falling into line with Western opinion on how to deal with Tehran’s defiance on meeting international demands to halt sensitive nuclear work.
After meeting French President Nicolas Sarkozy in Moscow on Wednesday, he signalled that he still disagrees with Western accusations that Iran is using a civilian nuclear programme as a cover for making atomic weapons.
Merkel is also expected to raise the issue of freedom of speech in Russia.
On Saturday Rice criticised the extent of Putin’s grip on power after meeting Russian human rights activists.
The talks in Wiesbaden are part of the Petersburg Dialogue, a civil society forum set up by Putin and former German chancellor Gerhard Schroeder to bring their two countries closer together.
At the start of the conference, former Soviet leader Mikhail Gorbachev defended Putin against Western criticism, saying he had done “a very good job” and had continued the process of reform begun by Gorbachev.
