A patent fight is heating up between construction-equipment makers Caterpillar Inc. and Wirtgen Group Holding GmbH of Windhagen, Germany, over milling and paving machines.

The latest action is the U.S. International Trade Commission's Nov. 22 announcement that it will launch a probe in response to a Caterpillar filing against Wirtgen.

Caterpillar is asking the ITC to issue a 'permanent limited exclusion order' to bar machines and equipment that allegedly infringe on its patents.

In its complaint, filed on Oct. 26, Caterpillar alleged that Wirtgen Group Holding and three of its subsidiaries sold road-construction equipment in the U.S. that infringe on Caterpillar patents. The filing was posted by the independent ITC 337 Law Blog.

Caterpillar is asking the ITC to issue a "permanent limited exclusion order" to bar machines and equipment that allegedly infringe on its patents. It also wants the commission to issue a cease-and-desist order against Wirtgen's importing, advertising, distributing and licensing such machines in the U.S.

In August, the ITC had said it would open an investigation of a complaint filed by Wirtgen America Inc. alleging patent infringement by Caterpillar.

Both companies allege violations of the 1930 Tariff Act.

Wirtgen America, based in Antioch, Tenn., said in its filing, posted by ITC 337 Law Blog, that it had filed two patent-infringement lawsuits in June—one in federal district court in Delaware against Caterpillar Inc. and the other in federal district court in Minnesota against Caterpillar Inc. and four of its subsidiaries.

Wirtgen also said that its road-milling revenue rose to about $541 million in 2015 from $58 million in 2000.

According to Caterpillar, both federal court cases have been stayed pending the ITC's decision on Wirtgen's complaint.