SOFIA - Some 75 percent of the agreement on Britain's exit from the European Union (EU) has already been negotiated, Bulgarian Foreign Minister Ekaterina Zaharieva said here on Tuesday.

In the first phase of the negotiations, it was agreed to guarantee the rights of all European citizens, a topic that was a priority for her country, Zaharieva said at a discussion about the impact of Brexit on the EU and Bulgaria.

An agreement has also been reached on Britain's financial commitments, with London participating in the EU budget by the end of the current seven-year programming period -- 2020, Zaharieva said.

The border between Ireland and Northern Ireland remained a serious issue, she said.

Due to Brexit, the UK would leave 750 agreements with the EU, and this would undoubtedly affect all spheres of public life, Zaharieva said.

"It is very important to ensure predictability and security for EU citizens and businesses," said Zaharieva, who is also Bulgaria's deputy prime minister.

According to Zaharieva, the EU-UK relations should not be limited to a free trade agreement.

Cooperation should be sought in security, foreign policy and defense, as well in the social sphere, with a focus on labor mobility, culture and education, she said.