German luxury carmaker BMW on Friday said it was recalling "approximately one million vehicles" in North America over two separate problems that posed fire risks, and did not rule out that more countries may be affected.

The largest of the recalls covers over 740,000 328i, 328xi, 328i xDrive, 525i, 525xi, 528i, 528xi, 530i, 530xi, X3 3.0si, X3 xDrive30i, X5 xDrive30i, Z4 3.0i, Z4 3.0si and Z4 sDrive30i vehicles from 2007-2011. Also included is the 2008-2011 128i. All have 6-Cylinder engines.

Documents posted Friday by the U.S. National Highway Traffic Safety Administration show that a heater for the positive crankcase ventilation valve can overheat and cause the valve to melt, increasing the risk of a fire even when the vehicle is not in use. No injuries have been reported. Dealers will replace the heater.

The heater is designed to prevent the valve from freezing in cold temperatures, BMW spokesman Hector Arellano-Belloc said. But irregularities in manufacturing can cause corrosion can lead to overheating.

The other recall covers nearly 673,000 cars including the 323i, 325i, 325xi, 328i, 328xi, 330i, 330xi, 335i, 335xi and M3 from the 2006-2011 model years. Also covered are the 2007-2011 328i xDrive, 335i xDrive and 335is, and the 2009-2011 335d.

Wiring for the heating and air conditioning system can overheat and cause connectors to melt, also increasing the fire risk, even when vehicles are unattended. Four drivers reported injuries.

Both recalls are for some 700,000 cars each but because there are "a lot of overlaps" the total number of affected cars is around one million, spokesman Michael Rebstock told AFP.

Most of the recalls affect the United States, while some 15,000 cars are being recalled in Canada.

"We don't exclude" that other markets beyond the U.S. and Canada could be subject to the same recall actions, the spokesman said, adding that BMW was already in talks with authorities in Europe.

"It must be seen if other countries could be considered," he said.

The affected cars were produced in Spartanburg, South Carolina as well as in Germany, South Africa and several other countries, the spokesman said.

The mass recall is the latest setback to hit the German titan, after its Munich headquarters was raided by EU antitrust regulators late last month as part of a probe into alleged collusion between German carmakers.

News of the recalls barely affected BMW shares on Frankfurt's blue-chip DAX index however, with the manufacturer shedding 0.33 percent to close at 89.57 euros.

Recalls in the US can potentially lead to major damages claims.

Earlier this year, four automakers including BMW and Toyota agreed to pay $553 million (476 million euros) to settle a U.S. lawsuit over defective Takata airbags that were blamed for at least 16 deaths.