The U.S. Senate has voted Thursday to reject attempts to limit debate on an immigration reform bill, extending opportunities to amend it before it goes to a final vote.
The fate of the compromise bill appears in doubt, since amendments could upset the carefully crafted compromise measure.

Thursday's vote means senators can keep bargaining on the bill for now. But if discussion drags on too long, Democratic leadership could remove the bill from consideration.  Another test vote is expected later Thursday.

Earlier, lawmakers worked on several amendments, including one that would shut down a proposed guest worker program after five years.  Another amendment proposes to make English the official language of the U.S.

A bipartisan group of U.S. senators reached an agreement with the Bush administration last month on a compromise bill that would provide legal status for undocumented workers, while increasing border security. 

The bill has come under attack from the left and the right, with some immigration groups saying it is too tough on immigrants and some conservatives calling it an amnesty.

Some information for this report was provided by AP.