BERLIN (AFP) - The Soviet Union's last leader Mikhail Gorbachev warned on Saturday that the world was on the "brink of a new Cold War" at an event to mark 25 years since the Berlin Wall's fall, the German news agency DPA reported.

"The world is on the brink of a new Cold War. Some are even saying that it has already begun," the 83-year-old said, amid tensions between the West and Russia over Ukraine.

He complained of a "breakdown of trust" in recent months, adding: "Let us remember that there can be no security in Europe without German-Russian partnership."

He was attending an event organised by the Cinema for Peace Foundation, formed in Berlin in 2008.

Gorbachev, whose "perestroika" and "glasnost" reforms helped pave the way for the Wall's fall on Nov 9, 1989, is attending three days of festivities in the German capital to mark the event.

In an interview with Switzerland's RTS radio and TV network, due to aired on Sunday, Gorbachev said: "One sees new walls. In Ukraine, it's an enormous ditch that they want to dig."

He said Nato was no longer necessary but "wants to prove that it can save the world".

On Thursday he had said he would seek to defend Russian President Vladimir Putin's policies when he travelled to Germany and said he was convinced the Ukraine crisis provided an "excuse" for the United States to pick on Russia.