The A14 in west Suffolk was closed for several hours overnight after a serious crash involving a number of vehicles.
The incident happened on the eastbound carriageway between junction 36 for the A11 and junction 37 for Newmarket shortly before 6pm on Thursday, National Highways said on Twitter.
Two of the three lanes were initially closed, before National Highways confirmed the eastbound carriageway was completely shut shortly before 3am on Friday.
The road reopened several hours later after 5am.
A police spokesman later confirmed two people had been seriously injured in the crash.
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