Ford said this week it was recalling 1.22m pickup trucks in the United States and Canada over concerns about fuel tanks dropping and causing fire — the latest in a series of recalls this year.

The recall includes the 1997-2003 Ford F-150, 2004 F-150 Heritage, 1997-99 F-250 — versions below 8,500 pounds — and 2002-03 Lincoln Blackwood pickups, according to the Detroit News.

The US recall includes 1.1m vehicles in 21 states and Washington, DC, to replace fuel tank straps which can corrode after extended periods — often in high corrosion areas — and allow the fuel tank to drop and potentially leak, which could lead to a fire, Ford was cited as saying.

The National Highway Traffic Safety Administration (NHTSA) in May upgraded an investigation into 2.7m Ford pickup trucks over this issue, the paper noted. NHTSA said earlier this week its investigation is continuing into the remaining 1.6m pickups that haven't been recalled.

"Our investigation is still open until NHTSA can fully evaluate the steps Ford has taken [this week]," agency spokeswoman Lynda Tran was quoted as saying.

Ford has now recalled nearly 3m vehicles in 2011; by contrast it recalled just 570,000 vehicles in all 2010, the Detroit News said.

NHTSA had said in May it had 243 reports involving the fuel tank dropping below the vehicle and/or dragging on the ground, 95 involved fuel leakage, and nine included reports of sparks from the tank being dragged on the road.

NHTSA had one report of strap failure in which the leaking fuel ignited but self-extinguished. Ford reported another incident in which the leaking fuel ignited and the resultant fire destroyed the vehicle.

The report said Ford would notify owners in mid-September and ask them to take their vehicles to dealers for repair. Ford is aware of three vehicle fires and one injury associated with this condition.

In April, under heavy government pressure, Ford expanded a recall of F-150 pickups and other vehicles over air bags that suddenly deployed in more than 260 cases. It ended up recalling over 1.3m vehicles over the issue.

In January Ford said it was recalling 425,000 Windstar minivans in 22 cold-weather states, including Michigan, to fix potentially corroded parts. The recall covers the 1999-2003 model years.

In March, Continental's North American unit said it was recalling 390,000 truck tyres following a fatal crash involving a Ford pickup in September. Most of the recalled tyres were used as original equipment on new F-250 and F-350 vehicles, the Detroit News said.

It added NHTSA is also investigating many other Ford issues. It recently said said it had upgraded an investigation into 317,000 Ford Fusion and Mercury Milan sedans on wheel issues.