A group of Democratic senators in swing districts is urging President Barack Obama to make a decision on whether to approve the controversial Keystone XL pipeline soon, according to analysis in Oilprice.com.

With midterm elections looming, the 11 senators—most of whom have a history of supporting the oil industry—wrote a letter asking the administration for a "definitive timeline" on construction of the TransCanada project by the end of May, Oilprice said.