Russian President Vladimir Putin and German Chancellor Angela Merkel attend a wreath laying ceremony at the Unknown Soldiers's Tomb on May 10, 2015 in Moscow, Russia. Alexander Aksakov | Getty Images

Russian President Vladimir Putin arrives in Berlin this weekend to meet with German Chancellor Angela Merkel and the two world leaders will have plenty to talk about. It is the second time in three months that the pair have met after Merkel traveled to the Russian coastal resort of Sochi in May. On this occasion, Merkel will host Putin at the German government's castle in Schloss Meseberg, just outside Berlin. Talks are due to begin Saturday at 6:00 p.m. local time (midday ET). The meeting has been hastily arranged and was only announced Monday this week when Merkel's spokesperson Steffen Seibert named the key topics the pair would concentrate on: Syria, Ukraine and the Nord Stream 2 pipeline.

That agenda was confirmed by Kremlin spokesman Dmitry Peskov who, when asked whether the leaders would also discuss American sanctions, including potential measures against German companies, said, "they will, obviously they will."

Berlin and Moscow: It's complicated

Merkel and Putin have regularly clashed in the past. Most notably, the German leader fruitlessly attempted to persuade Putin of a diplomatic solution when war raged in the eastern region of Ukraine in 2014. Merkel also annoyed her Russian counterpart in 2012 when she questioned a two-year jail sentence for the band Pussy Riot who had sung anti-Putin "punk prayer" in a Moscow cathedral. Putin rebuked Merkel, suggesting she did not known all the facts of the case. In August, the U.S. administration said it would impose further sanctions against Russia as punishment for the alleged use of a nerve agent in an apparent assassination attempt on a former spy that ultimately killed a British citizen. Merkel joined President Donald Trump, French President Emmanuel Macron and British Prime Minister Theresa May in a rare joint statement that said "there is no plausible alternative explanation" to Russian responsibility. But on other issues the pair have agreed, and they are currently united in maintaining the 2014 Iran nuclear accord that saw several world powers remove sanctions on Iran in exchange for the Middle Eastern country agreeing to stop enriching uranium. The United States pulled out of that agreement and in May the U.S. ambassador to Germany, Richard Grenell, said German businesses should immediately wind down any operations in Iran. John Bolton, Trump's national security advisor, then added that European companies that do business in Iran could face U.S.-imposed economic sanctions. Moreover, a new gas pipeline linking Russia to Germany, known as Nord Stream 2, has given the two countries a potential common cause. But, the United States sees the pipeline as a reach of Russian control into Western Europe and has threatened further sanctions on Moscow, which could have knock-on effects for German firms. Although, the U.S. has given assurances that the new penalties won't affect the building of the gas pipeline. In an email to CNBC Friday, the managing director of political consultancy Teneo Intelligence, Carsten Nickel, said that while Trump's threat of Nord Stream 2 related sanctions affected both countries, it would not bring about a German pivot toward Moscow. "Instead, it demonstrates that a fundamental pattern remains the same as in the (Barack) Obama days: Merkel, not the White House, is Putin's key interlocutor in the West," said Nickel.

Nord Stream 2

Germany and Russia want to build the Nord Stream 2 pipeline which would allow Russian gas to flow into Europe without passing through Ukraine.

The route of a proposed new gas pipeline from Russia to Europe. nord-stream2.com

The project has come under much criticism as some analysts feel it will leave Europe reliant on Russian energy as stocks from Britain, Denmark and the Netherlands dwindle. Ukraine would lose billions if the project to route the pipeline under the Baltic Sea is completed, and in July the Ukrainian president described it as "absolutely a geopolitical project" that made no economic sense. Nickel said that Merkel would use Saturday's talks to press Putin on maintaining an energy commitment to Ukraine. "Merkel's goal will be to have Putin substantiate indications that Russia might still transfer some of its westbound gas deliveries through Ukraine, even after Nord Stream 2 becomes operational," he said. "That might help at least somewhat diffuse respective concerns in Eastern Europe and in Washington," Nickel added. Kristine Berzina, an analyst at thinktank The German Marshall Fund of the United States, told CNBC Friday that Nordstream 2 would be the "prickliest" topic of conversation between Putin and Merkel. In a telephone call from Brussels, Berzina said she was concerned about the principle of Russian guarantees to maintain some sort of gas transit through Ukraine. "This is the moment, before Nordstream 2 is built, that Germany has the most leverage over Russia," she said, before adding that Merkel must secure the strongest possible assurances from Putin now, as she would hold no sway over Moscow once the pipeline was up and running in 2020.

Ukraine

The war in eastern Ukraine began in early 2014 and skirmishes continue between Russian separatists and forces loyal to the Ukrainian government.

Orthodox priests stand among pro-Russian armed men blocking access to the Ukrainian frontier guard base in Balaklava, a small city not far from Sevastopol, on March 1, 2014. Viktor Drachev | AFP | Getty Images

Russia has taken control of the Crimean Peninsula and there are reports that Russian troops are still involved in fighting in the country's eastern region. This has led to sanctions from EU countries, including Germany, which are still in place. Berzina said the main areas of conversation between the two leaders will circle around ongoing skirmishes in the Black Sea and the role of peacekeepers in the Donbass region of Ukraine. The analyst added it was unlikely that any request by Merkel for United Nations troops to police a cease-fire was likely to interest Putin. "I don't know whether progress is possible on any of these issues and what leverage Merkel might have," she said. Berzina added that Merkel's focus on Ukraine with Putin may remain on preventing an escalation of conflict, rather than finding a long-term solution.

Syria

Reports vary, but between 300,000 and 500,000 people are believed to have been killed in Syria since the conflict began in 2011.

A handout picture released on the official Facebook page of the Syrian Presidency on December 11, 2017 shows Russian President Vladimir Putin (R) meeting with his Syrian counterpart Bashar al-Assad in the Russian air base in Hmeimim in the northwestern Syrian province of Latakia. Syrian Presidency Facebook page | AFP | Getty Images

Syrian President Bashar Assad has largely crushed opposition forces, which initially challenged his regime over the release of political prisoners and called for his resignation. Russian support of Assad has been crucial to the Syrian leader's ability to maintain a grip on power as he has defeated opposition forces. Currently Assad is launching a new offensive in the country's northwest where the remaining Syrian rebels have been cornered. It is thought Merkel may ask Putin to exert his influence over Assad in a bid to avoid further widespread bloodshed. In early September Turkish President Recep Tayyip Erdogan is set to host a four-way summit on Syria, also attended by France, Germany and Russia.

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