A minivan carrying seven Michigan tourists to Niagara Falls crossed a median on Interstate 90 and was hit by an oncoming car, leaving six people in the van dead, police say.

The minivan was about three miles inside the Pennsylvania-Ohio border around 4 p.m. Saturday when it crossed the highway and began flipping and rolling, coming to rest on its roof, authorities said.

It was then struck by an oncoming westbound car, whose driver was treated at a hospital and released Saturday night, said state police Cpl. Kevin Havern.

Minivan driver Kaushik Deb, 26, of Troy, Mich., in suburban Detroit died on impact. The passengers killed were Manoj Jharia, 35; Mili Jharia, 28; Nitin Agarwal, 29; Swati Agarwal, 25; and Shubham Choudory, 24. The Jharias and Agarwals were married, police said.

The sole survivor in the minivan, Nitin Gupta, 28, was sitting in the front passenger seat, Havern said. He was also treated and released from a hospital Saturday.

The seven tourists were citizens of India, police said. Four of the six killed were employees of Troy, Mich.-based Syntel Inc., and two were spouses of employees, Jonathan James, vice president for marketing and investor relations, said Sunday. He said the company would have further comment later Sunday morning.

The seven were traveling with another van carrying six people that was a few minutes ahead of them.

The two groups had just left a rest stop and traveled about a quarter-mile when the accident occurred, said Kranthi Bandaru, who was traveling in the second van.

"We left them about 10 minutes before they drove on," Bandaru told the Erie Times-News. "We continued down the road when we received a cell phone call from Nitin that there was an accident. That's when we turned around."

State police said there was no apparent cause of the crash. Erie County Coroner Lyell Cook said he has ordered toxicology tests for minivan's driver.

Syntel is an information technology company with 27 offices and 12,000 employees worldwide and 2007 revenues of $337.7 million, according to its Web site.