BEIRUT—Syrian warplanes bombarded rebel-held areas near the capital Damascus and in the center and north of the country Wednesday, the latest round of attacks in an intensified campaign of airstrikes that began a week ago.

At least 10 people, including women and children, were killed and dozens wounded after planes fired missiles and dropped bombs on the rebel-held city of Douma, about 10 miles northeast of Damascus, said opposition activists. They hit several targets in Douma, including a market.

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