Microsoft is accusing US Customs officers of refusing to block imports of certain Motorola smartphones in a new complaint filed today in a US district court. According to Bloomberg News, Microsoft claims in the complaint that Customs has continued to allow Motorola Android smartphones into the country after the International Trade Commission (ITC) ruled last May that the devices infringed a 1998 patent held by the Redmond-based company. The patent involves syncing contact information and email addresses across PCs and mobile devices, and many other Android manufacturers have a licensing agreement with Microsoft to cover use of the patent.

"Customs repeatedly ignored its obligation and did so based on secret discussions.”

In the complaint, Microsoft says that Google-owned Motorola got a grace period on the ITC order after holding secret meetings with US Customs to convince officers that the import ban only applied to data sent over Microsoft's servers — not Google's. Microsoft says such requests had already been denied by the ITC. In a statement supplied to Bloomberg News, Microsoft's deputy general counsel David Howard says, "Customs repeatedly ignored its obligation and did so based on secret discussions.”

The ITC ruled in Microsoft's favor in May 2012, placing an exclusion order on the infringing Motorola devices. A month after that decision Motorola offered to settle with Microsoft with a meager 33-cent license fee per phone.