(CNN) House Democrats on Monday unveiled an initial 2020 battlefield map, targeting 33 Republican-held or open congressional seats with an emphasis on suburban districts -- and Texas in particular.

The target list was released in a strategy memo from Illinois Rep. Cheri Bustos, chair of the Democratic Congressional Campaign Committee, and DCCC executive director Allison Jaslow, who announced that the committee "is gearing up for an aggressive effort to fortify and expand" the majority won by House Democrats in 2018.

"As the saying goes, the best defense is a good offense, and we couldn't agree more," they wrote.

"2018 was just the tip of the iceberg for Democrats," said Bustos. "Today we are announcing our plan to go on offense and grow our New Democratic Majority. We have a clear path to expanding our Democratic Majority, and by putting our plans in motion earlier in the cycle than ever before, we are demonstrating to Democrats across the country that the political arm of House Democrats is operating in high gear from the start.

Looking to build on their success targeting such seats in the recent midterms, the Democrats said that "many of the districts on our list have big suburban populations; many have also experienced rapid population growth in recent years -- particularly in diverse communities" and described the districts as "ripe pick-up opportunities."

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