BRUSSELS (AP) - The European Union's president warned Britain on Thursday he's open to suggestions on how the bloc must change, but won't compromise on the EU's "fundamental values."
EU President Donald Tusk spoke as bloc leaders gathered for a summit in Brussels.
British Prime Minister David Cameron said he'll use the two-day event to explain to fellow heads of state and government the 28-nation EU must reform or risk losing the backing of a majority of British voters.
Cameron and his Conservative Party won a general election in May. Cameron has promised a referendum by 2017 on whether Britain, an EU member since 1973, stays in the bloc or not.
But Tusk warned some things aren't up for discussion.
"The fundamental values of the European Union are not for sale and so are non-negotiable," Tusk said, without specifying what the values were.
Many Britons think the EU meddles too much in their lives, and that their country has ceded too much authority to Brussels. British officials said Cameron wants the EU to focus more on its core competencies like increasing economic competitiveness, and give up the quest for "an ever closer union" in many other fields, like laws on the freedom of movement.
European Parliament President Martin Schulz said he and other members of the legislature were waiting to hear "concrete proposals" from Cameron.
Schulz, who visited London last week for talks with the British leader, said the EU could easily reach a deal "if the British government makes concrete proposals that will make the EU more democratic, more effective and transparent, and will deepen the single market."
But Schulz, whose home nation of Germany is one of the EU's most influential members, said Cameron shouldn't ask for too much.
"Solutions are not brought about by one member state making demands and expecting the others to deliver," he said. "Solutions can only be found by making proposals that will contribute to the common good."