Google has announced plans to acquire Russia-based contextual ad firm ZAO Begun for $140m.

The search giant hopes that the buy will increase its advertising reach in the fast-growing Russian market.

Google claims that the deal will allow its advertisers to reach a larger group of websites in the region, and allow for better targeting of ads on Russian sites.

"The entire industry will benefit from this transaction as there is a high potential for synergies," said Alexey Basov, general director of ZAO Begun.

"It brings together Google's visionary technology and Begun's six years of successful experience in building advertising and dealer networks and direct sales in Russia."

Google said that it hopes to close the transaction by September and begin allowing users to purchase ads within the ZAO Begun website network soon after.

"Google is very committed to giving Russian users, advertisers and partners the best possible service and experience," said Mohammad Gawdat, managing director for emerging markets at Google.

"This agreement will result in better search results and more relevant advertising for our Russian users and publishers."