Prime Minister David Cameron predicted there would be "ups and downs" in Britain's bid to renegotiate its relationship with the European Union as he arrived at a summit in Riga Friday.

"There will be lots of noise, lots of ups and downs along the way," he said, while voicing "determination" to secure EU reforms ahead of a referendum by the end of 2017 on a possible British exit.

"It's in Britain's interest that this is a success," Cameron added on arrival at the summit between leaders of the EU and six former Soviet states.

Cameron backs staying in the European Union as long as he can secure reforms such as controlling migration by making it harder for EU migrants to claim state benefits in Britain.

His trip to Latvia is his first foreign visit since his centre-right Conservative party won this month's general election with a surprise though slender overall majority.

British officials said Friday Cameron will also travel to Paris and Berlin next week for talks.

As they arrived for the summit dinner Thursday, EU leaders were repeatedly asked what they would say to Cameron on Friday in their first meeting since the May 7 election.

German Chancellor Angela Merkel made no comment, while French President Francois Hollande responded with a terse: "Oh, I do not think that is this evening's subject."

"This is not a meeting concerning UK membership," said European Commission head Jean-Claude Juncker, who will be a key figure in the negotiations.