The United States and Iran said Monday they had made some progress in the latest round of talks on Tehran's nuclear program, but warned there was still a long way to go to reach a final deal.

Negotiators for Iran and six world powers have held a range of meetings in Geneva since Friday, and plan further talks in the city next week, a senior U.S. administration official said.

Germany's foreign minister warned Sunday in comments to a newspaper that any attack on the eastern Ukrainian city of Mariupol would be a clear violation of a week-old ceasefire accord.

Asked by Germany's Bild newspaper where, for him, the red lines in the Ukraine conflict lay, Frank-Walter Steinmeier said they had been drawn in the Minsk ceasefire deal that Germany helped broker.

Thousands of pro-Kremlin activists took to the streets of central Moscow on Saturday vowing to prevent a Ukraine-style uprising in Russia.

The rally by the Anti-Maidan movement marked one year since scores of demonstrators were gunned down in Ukraine's pro-Western uprising that came to be known as the Maidan protests.

Australia on Friday said France, Germany and Japan were potential partners to design and build its next generation of submarines, in what will be its biggest ever defense procurement program.

As Canberra seeks to replace its ageing Collins Class fleet, Defense Minister Kevin Andrews said all three countries had proven military design and build capabilities and were currently producing submarines.

A German former nurse who has admitted killing over 30 hospital patients with lethal injections in a thrill-seeking game to try to revive them apologized on Thursday to relatives of the victims.

"I am honestly sorry," the 38-year-old said at his trial, where he so far faces three murder charges, adding that he had usually acted on impulse when he injected patients with lethal drug doses.

The leaders of Russia, Germany and Ukraine have agreed on "concrete measures" to allow OSCE observers to monitor the shaky ceasefire in Ukraine, Berlin announced on Tuesday.

The measures were agreed during a late Monday phone call between German Chancellor Angela Merkel and her Russian and Ukrainian counterparts, Vladimir Putin and Petro Poroshenko, the government spokesman said in a statement, without providing details of the agreed steps.

Germany said Monday it wants Jews to stay and promised to ensure their security following a deadly attack on a Danish synagogue and calls from Israel for European Jews to emigrate. 

Chancellor Angela Merkel said Germany was "glad and also grateful" to have a Jewish community, when asked about Israeli Prime Minister Benjamin Netanyahu's renewed appeal following Sunday's attack in Copenhagen.

Germany's carnival celebrations drew hundreds of thousands on to the streets Monday, despite fears of possible jihadist violence as the traditional "Mardi Gras" parade reflected themes of terror attacks and freedom of speech.

Authorities were on guard following the shootings in Copenhagen at the weekend and the cancellation of the carnival procession in the northern German city of Brunswick Sunday because of the threat of an "Islamist attack," local police said.

The controversial sale of two high-tech warships to Russia is "not on the agenda", France's defense minister said on Monday, despite the ceasefire agreed in Ukraine last week.

"It's not on the agenda," Jean-Yves Le Drian told French radio.

The German city of Braunschweig canceled a planned carnival parade Sunday because of a "specific threat of an Islamist attack", police said.

The event, which was to begin at 1120 GMT, was called off following a tip by "reliable state security sources", police said in a statement.