The European Union and China on Tuesday expressed a desire to deepen cooperation on international security, diplomacy and climate change, though human rights appeared to remain a sensitive issue.

EU foreign policy chief Federica Mogherini and China's top foreign policy official Yang Jiechi held talks as part of a regular strategic dialogue in which the two sides exchange views and develop political and economic relations.

Mogherini, leading the EU side in the two-day discussions for the first time, said much of her talks with Yang covered international hotspot issues such as Ukraine, Iraq, Syria, Libya and Iran.

The two sides discussed "possibilities of strengthening our cooperation on security and defence", Mogherini said at a joint press appearance, citing what she described as their "extremely successful" anti-piracy cooperation in the Gulf of Aden.

"We also discussed the situation in Iraq and Syria, briefly, and Libya where the European Union and China share common interests and where our joint efforts could make a real difference," she said.

Yang said that the two sides "agreed to step up communication and coordination" on key global issues such as Iran, where Beijing participates in negotiations with Tehran aimed at containing its nuclear programme as part of the so-called P5+1 -- Britain, China, France, Russia, the United States and Germany.

Mogherini was effusive in her praise of China's contribution, thanking it for what she called its "precious role" in the negotiations.

- 'Constructive exchange' -

Human rights, however, appeared awkward to address.

Mogherini said that she and Yang would continue talks after the press appearance -- at which neither took questions -- and stressed that "internal developments" in the EU and China would be discussed.

She expected there would be "constructive exchange on human rights issues as well on the importance of fostering dialogue with and between different ethnic groups" as well as discussions on "civil society" -- all sensitive topics for China.

Yang made no mention of human rights, but suggested that there were areas where they are bound to disagree.

"Given the breadth and depth of our relationship it would be unlikely for our two sides to see eye to eye on everything," he said, adding that provided there is "mutual respect" differences can be "properly" resolved.

Human Rights Watch last week urged Mogherini to "express publicly and privately to senior Chinese leaders the European Union's concerns about the deteriorating human rights environment" in the country.

It cited abuses of government critics, activists, lawyers, journalists and academics, including imprisoned 2009 Nobel Peace Prize winner Liu Xiaobo and ethnic Uighur economist Ilham Tohti, who is serving a life sentence after being convicted of separatism.

The Washington-based International Campaign for Tibet also called for what it called the "worsening human rights situation" in the Himalayan region to be raised.

Mogherini said that she and Yang reiterated that the conflict in Ukraine must be solved diplomatically, respecting the country's "territorial integrity and independence".

The EU is at odds with Russia over the annexation of Crimea and fighting in Ukraine, while Moscow and Beijing are drawing closer.

The latest talks come as the two sides this year mark the 40th anniversary of relations and prepare for a summit set for June in Brussels.

Relations have shown dramatic development over the decades, especially in the field of trade and commerce. The EU is China's biggest trading partner, while China is Brussels' second-largest.

Mogherini said that China and the EU were dedicated to ensuring a crucial UN climate conference this year in Paris would be successful and felt a "common joint responsibility" toward that end.

Mogherini also brought up the 70th anniversary of the end of World War II, saying the EU "pays tribute to the enormous sacrifices made by the Chinese people", apparently referring to the country's massive loss of life when it was invaded and occupied by Japan in the 1930s and 1940s.

But she also appeared to stress the need for reconciliation amid lingering regional tensions in Asia, citing Europe's post-war experience, stressing that "a common peaceful future" is "the only way to build a common respectful vision of the lessons of the past".