British Prime Minister David Cameron and Russian leaders set aside their political differences Monday to sign multi-million dollar business deals in a rare visit to Moscow by a British leader.

Mr. Cameron's day-long visit was the first by a British leader in six years, and clinched business deals worth about $340 million.

The British leader spoke with Russian President Dmitry Medvedev and Russian Prime Minister Vladimir Putin, breaking years of icy relations.

Relations between the two countries soured in 2006 after a former Russian security agent, Alexander Litvinenko, died of polonium poisoning in London.

Mr. Medvedev, at a press conference earlier Monday, flatly refused to extradite a Russian suspect wanted by Britain in the case, echoing previous refusals by Moscow. The British prime minister said their differences should not “freeze” their relationship.

Shrugging off the divisions, Mr. Cameron held talks with Mr. Putin — the first such contact by a British official with the Russian prime minister in four years — on promoting economic relations between the two countries.

Traveling with Mr. Cameron is a large business delegation, including top executives from BP, Royal Dutch Shell and Rolls Royce.

Speaking to students at Moscow University Monday, Mr. Cameron stressed being candid about the divisions that still separate the two nations, including disagreement on how to handle Syria.