British Prime Minister David Cameron and Russian leaders set aside their political differences Monday to sign multi-million dollar business deals during 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. He clinched business deals worth about $340 million.

The British leader spoke with Russian President Dmitry Medvedev and Russian Prime Minister Vladimir Putin.

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

Mr. Medvedev again Monday flatly refused to extradite a Russian suspect wanted by Britain in the case. But Mr. Cameron said their differences should not “freeze” their relationship.

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

A senior Medvedev aide said Mr. Cameron spoke to Mr. Medvedev about BP's interest in remaining active in Russia after an Arctic exploration partnership deal collapsed in May. The aide said that authorities cannot intervene in affairs between BP and the Russian oil firm Rosneft. He said Mr. Medvedev told the prime minister that such matters can only be settled in the courts.

A multi-billion dollar plan for BP to team up with Rosneft to look for oil in the Arctic Ocean fell apart in May over a feud between BP and Russian investors. Russian security forces raided BP's Moscow offices last month searching for documents related to the failed deal. BP said there was no legitimate basis for the raid. A Siberian court plans to hold a hearing on the Arctic deal next month.

Russian police also raided the BP Moscow office in 2008 as part of a fight over control over a BP-Russian joint venture.