WASHINGTON — Sen. Rob Portman, returning from a six-day trip to the Middle East, said Monday he’s concerned that impending deadlines for removing troops from Afghanistan are influencing decisions there, rather than the conditions on the ground.

“That concerns me,” said Portman.

In a call from the United Arab Emirates, Portman made it clear that the risks in Afghanistan are still very much evident: On Sunday, he said, he visited a forward operating base 30 miles from the Afghanistan-Pakistan border where an improvised explosive device exploded May 29, injuring three soldiers.

Later that night, he visited a hospital at Bagram Air Force Base — only to run into a wounded gunner who had been on the helicopter that had dropped him off at the forward operating base. Hours after leaving Portman at the base, the gunner was shot in the arm.

The trip, which also included a visit to Jordan and to Israel, spurred speculation the Ohio Republican was using it to highlight his foreign policy credentials. Portman is often mentioned as a possible running mate for presumptive Republican presidential nominee Mitt Romney.

Portman insisted he was doing nothing of the sort.

Instead, he said, the trip had been planned well in advance, and he said he took advantage of what are increasingly rare opportunities to visit the Middle East. With 23,000 troops to be withdrawn from Afghanistan by September, he said, there are few chances for members of Congress to visit the troops while they are there. He said he expects there will be no authorized Senate visits beginning next month, when the demobilization begins.

He’d originally been scheduled to go on part of the trip with Sen. Joe Manchin, D-W.Va., but Manchin ran into weather problems that prohibited his flight from taking off. He spent part of the trip with two House members, however.

Late last week, Portman visited Israel alone, where he met with Prime Minister Benjamin Netanyahu and Defense Minister Ehud Barak.

He said he talked to Barak about the Lima Tank Plant, which is producing parts of a new vehicle Israel is using, and urged Barak to consider having the entire vehicle produced in Lima.

The tank plant has begun fighting annual battles with the Obama administration, which has proposed cutting back on production of the M1 Abrams tank. Congress, however has consistently resisted the cuts.