WARSAW/BERLIN:  German Chancellor Angela Merkel visits Warsaw on Tuesday amid signs its conservative rulers are keen to repair the co-operation essential for European Union (EU) attempts to handle economic and political problems ahead.

Merkel needs the backing of Poland's government, wary of any increased powers for Brussels, to agree reforms in March, on the 60th anniversary of the founding Rome Treaty. The anniversary falls in the same month Britain plans to give notice of leaving.

Merkel will hold a rare meeting with Law and Justice party (PiS) leader Jaroslaw Kaczynski, who holds no government posts but is widely seen as the country's main decision-maker.

Ties were frosty when the PiS last governed Poland, between 2005-07, with Kaczynski making criticism of Germany central to campaigning to bolster the party's nationalist message.But diplomats say Poland is feeling under pressure with Britain's decision to leave depriving it of a strategic ally within the EU and the election of Donald Trump as U.S. President raising questions over the West's relationship with Russia.

"I can imagine that Poland is feeling vulnerable in the current environment, with Trump making overtures to Russia and Britain leaving the EU," a German diplomat told Reuters. "This could push them towards Germany."

Poland had long seen Britain as its key ally in pushing a tough line on Russia over its conflict with Ukraine and in defense cooperation. The PiS had also hoped to find a partner in Britain for its calls to weaken the power of EU institutions.

Since it returned to power in 2015, its leaders have toned down their past references to the Poles' suffering during World War Two under the Nazi German occupation. Meetings at various levels of government have become significantly more frequent than before 2007.

TENSE PAST

Obstacles to finding common ground in Tuesday's talks include Poland's hostility to resettling refugees from the Middle East, and international accusations that Kaczynski's government is veering into authoritarianism.

Merkel comes to Warsaw shortly before the expiration in late February of a European Commission deadline for Poland to address concerns over its handling of the constitutional court, which critics at home and abroad say undermines democratic standards.

"Close cooperation with the EU, mainly Germany and France, would be the main strategic interest for Poland," said Thomas Nord, an opposition German parliamentarian.

Some areas of agreement exist. Poland and Germany are keen to see more EU defense cooperation after Britain's departure and a strengthening of the bloc's external borders, for example.

But Tuesday's talks take place in the shadow of Kaczynski's deep-running mistrust of Germany, and of Merkel, arguably the most powerful figure in the EU. The Chancellor retains a key role in handling economic problems in, for instance, Greece and Italy while wielding great influence on the international stage.

In his 2011 autobiography, Kaczynski recalled Merkel, 62 trying to find common ground, evoking hers and his upbringing behind the Iron Curtain, in their conversations.

"She frequently repeated that she had visited Poland many times, knew socialism, that her experience meant one should speak with her differently," Kaczynski wrote.

Although born in the West, Merkel moved with her family to communist East Germany when she was a child and grew up near the Polish border.

"She was trying to soften her interlocutor. But there is no doubt that Merkel belongs to a generation of German politicians who want to rebuild Germany's imperial power ... Our country has to be in some way subordinate."

Kaczynski, who has said he hopes Merkel will secure another term in this year's German election, routinely refuses to see ambassadors to Warsaw, including the German envoy, and has met few foreign leaders since the PiS returned to power.

He acknowledges relations are better now but has said lasting improvement depends on Merkel's government, in comments highlighting likely tensions ahead.

"We want good relations with the Germans but it is the Germans who need to make up their mind," he told conservative DoRzeczy weekly in an interview published on Monday.