Initial reactions from European capitals show that "nobody's happy" with the draft agreement that European Union president Donald Tusk unveiled on Monday, one European source said on condition of anonymity.
The lack of satisfaction so far is a sign that Tusk's proposal is fair and balanced, but also an indication that it could be hard to reach a deal at the February 18-19 meeting of the 28 EU leaders, the source added.
The British prime minister is now set to fly to Poland and Denmark today at the start of a whirlwind fortnight of diplomacy in a bid to win over his sceptical EU counterparts and secure an accord.
European diplomats in Brussels are set to hold their first full talks on the new proposals today, and will meet again next Thursday in a bid to iron out their differences and reach an agreement at the summit.
More From This Section
A British government source said however that "the mood is improving on that."
Spain is meanwhile dissatisfied with the European Commission, the executive arm of the EU headed by Jean-Claude Juncker, for not taking a tougher line on Cameron's demands for a limit to benefits for EU migrants working in Britain, another European source said.
Tusk's proposals include a four-year "emergency brake" limiting welfare payments to migrants, as well as "red card" system for national parliaments to overrule draft EU laws.