"The deal was signed for 3 1/2 years and the financial details will be disclosed tomorrow," Zenit spokesman Alexei Petrov said.

Arshavin helped Zenit win last season's UEFA Cup and has become Arsenal's biggest signing of the transfer window. While the clubs negotiated the deal, he flew to London to have medical checks.

Arshavin pushed for a transfer after an impressive European Championship last year, when he helped guide Russia into the semifinals.

Negotiations with Arsenal's north London rival, Tottenham, in the offseason broke down over the price tag.

The Gunners are fifth in the Premier League, 10 points behind leader Manchester United, and manager Arsene Wenger identified Arshavin as his main target to compensate for the losses of long-term injury absentees Cesc Fabregas, Tomas Rosicky and Theo Walcott.

Walcott, who was injured on international duty in November, is not expected to make his comeback from a dislocated shoulder until early next month.

"He has four weeks before he sees a specialist again and then he should get the green light," Wenger said Monday.

Fabregas said over the weekend that his recovery from knee ligament damage was ahead of schedule, but Wenger was less certain about the Spaniard's return.

"Fabregas, I believe, will be six to eight weeks before playing," Wenger said. "I can understand his optimism, and we hope (that he will be back quicker) but with a medial knee ligament you have to respect the time."

Rosicky, who has been sidelined for more than a year with a hamstring injury, will have to wait another eight weeks before returning.