Leaders at the EU summit in Brussels are trying to reach agreement on how much Europe will give the developing world to fight climate change, and will also discuss ratification of the Lisbon Treaty.
Czech Prime Minister Jan Fischer has said President Vaclav Klaus has pledged to sign the treaty if EU leaders grant the Czech Republic an opt-out from the Charter of Human Rights.
Mr Fischer hopes to negotiate the opt-out at the Brussels meeting, which would be similar to exemptions secured by Poland and Britain.
President Klaus, who is a euro-sceptic, is the only EU leader who has not signed the treaty.
Candidates for the new post of EU president are also up for discussion.
