A Dubai-owned company said Thursday it is giving up its entire stake in US ports, a move made as congressional leaders warned President George W. Bush that both the House of Representatives and Senate appeared ready to block the takeover. Lawmakers who have been trying to block the deal involving DP World said they were studying the company's announcement to see if it adequately addressed their concerns about an Arab government taking over major operations at six US ports. The deal has become an election-year burden for Republicans and a major political headache for Bush. Underscoring how much the issue has veered out of the Bush administration's control, the Senate rejected an effort by its own Republican leaders to thwart Democrats who want a vote on derailing the DP World deal. The Senate voted 51-47 to consider the Democratic legislation, falling 16 short of the 67 votes Republcian leaders needed to prevail.