WASHINGTON -- The number of VA facilities under investigation after complaints about falsified records and treatment delays has more than doubled in recent days, the Office of Inspector General at the Veterans Affairs Department said late Tuesday.

A spokeswoman for the IG's office said 26 facilities were being investigated nationwide. Acting Inspector General Richard Griffin told a Senate committee last week that at least 10 new allegations about manipulated waiting times and other problems had surfaced since reports of problems at the Phoenix VA hospital came to light last month.

The expanded investigations come as President Barack Obama's choice to help carry out reforms at the Veterans Affairs Department was set to travel to Phoenix to meet with staff at the local VA office amid mounting pressure to overhaul the beleaguered agency.

Obama announced last week that White House Deputy Chief of Staff Rob Nabors would be assigned to the VA after allegations of delayed care that may have led to patient deaths and a cover-up by top administrators in Phoenix. Similar claims have been reported at VA facilities in Pennsylvania, Wyoming, Georgia, Missouri, Texas, Florida and elsewhere.

Nabors met Tuesday in Washington with representatives of several veterans' organizations, including the American Legion and Disabled American Veterans, among others. He will meet Thursday with leadership at the Phoenix Veterans Affairs Medical Center, including with interim director Steve Young, White House spokesman Jay Carney said.

Young took over in Phoenix after director Sharon Helman was placed on leave indefinitely while the VA's Office of Inspector General investigates claims raised by several former VA employees that Phoenix administrators kept a secret list of patients waiting for appointments to hide delays in care.

Critics say Helman was motivated to conceal delays to collect a bonus of about $9,000 last year.

A former clinic director for the VA in Phoenix first came out publicly with the allegations of secret lists in April. Dr. Samuel Foote, who retired in December after nearly 25 years with the VA, says that up to 40 veterans may have died while awaiting treatment at the Phoenix hospital. Investigators say they have so far not linked any patient deaths in Phoenix to delayed care.

The allegations have sparked a firestorm on Capitol Hill and some calls for VA Secretary Eric Shinseki's resignation. The VA's undersecretary for health care, Robert Petzel, has since stepped down.

However, Republicans denounced the move as a hollow gesture, since Petzel had already been scheduled to retire soon. And several lawmakers are proposing legislation to take on VA problems.

Republican Sen. Jerry Moran of Kansas, a member of the Senate Veterans Affairs Committee, told The Associated Press on Tuesday he plans to introduce legislation this week to ensure that internal probes by the VA's Office of Medical Inspector are released to Congress and the public "so the full scope of the VA's dysfunction cannot be disguised."

Moran noted that a VA nurse in Cheyenne, Wyoming, was put on leave this month for allegedly telling employees to falsify appointment records. The action came after an email about possible wait-list manipulation at the Cheyenne hospital was leaked to the media.

But Moran said the Cheyenne center was already the subject of a December 2013 report by Office of the Medical Inspector. That report apparently substantiated claims of improper scheduling practices, but it's unclear if action taken at the Cheyenne center was based on the medical inspector's findings, Moran said.

"Because OMI reports are not available to the public and have not been previously released to Congress, it is impossible to know whether the VA has taken action to implement the OMI's recommendations for improvement in each case," Moran said.

Meanwhile, two Republican senators introduced legislation to prohibit payment of bonuses to employees at the Veterans Health Administration through next year. Sens. Richard Burr of North Carolina and Deb Fischer of Nebraska said the VA should focus its spending on fixing problems at the agency, "not rewarding employees entrenched in a failing bureaucracy." Burr is the senior Republican on the Senate Armed Services Committee and Fischer is a panel member.

The House passed a bill in February eliminating performance bonuses for the department's senior executive staff through 2018.

Texas Sen. John Cornyn, the No. 2 Republican in the Senate, also called on Obama to back off plans to nominate Jeffrey Murawsky to replace Petzel at the VA. Murawsky, a career VA administrator, directly supervised Helman from 2010 to 2012.

The White House has said Obama remains confident in Shinseki's leadership and is standing behind Murawsky's nomination.

Shinseki and Defense Secretary Chuck Hagel met with the House Appropriations Committee on Tuesday to discuss how the two departments can improve interactions between their health records systems. The two Cabinet members said in a joint statement that the meeting was productive and that both men share the same goal -- to improve health outcomes of active duty military, veterans and beneficiaries.

-- Associated Press writer Brian Skoloff in Phoenix contributed to this report.