July 22 (Reuters) - The U.S. House of Representatives approved a plan on Thursday to allow an extra 8,000 special immigration visas for Afghans who helped the United States and are at risk of retaliation as U.S. troops complete their pullout from Afghanistan after a 20 year war. The bipartisan bill, which passed with a vote of 407 to 16, will now be considered by the Senate. It also aims to speed up the processing of the visas. Representative Jason Crow, a Democrat who led the group that sponsored the bill, said the additional visas would cover all potentially eligible applicants in the pipeline. U.S. Secretary of State Antony Blinken acknowledged last month that there were about 18,000 possible applicants. The Special Immigrant Visa program is available to Afghans who worked with the U.S. government or U.S. military. The United States has granted 26,500 such visas since December 2014. President Joe Biden"s administration has been under pressure from lawmakers and advocacy groups to begin evacuating thousands applicants and their families after Biden said the U.S. military mission in Afghanistan would formally end on Aug. 31. "For too long, there has not been a sense of urgency that is necessary to ensure safety for the people who put their lives on the line to help Americans in these difficult circumstances," said Representative Earl Blumenauer, a Democrat. Concerns for the applicants also have been fueled by an increase in fighting between U.S.-backed Afghan forces and the Taliban in recent weeks, with the militants gaining territory and capturing border crossings. The United States this month will begin evacuating special immigration visa applicants from Afghanistan and the first batch will be taken to a military base in Virginia as they wait for the process to be completed. read more U.S.-backed Afghan forces toppled the Taliban in late 2001 for providing sanctuary to al Qaeda leader Osama bin Laden and its operations used to attack the United States on Sept. 11, 2001.