FRANKFURT - Warning strikes across Germany began early on Tuesday morning, affecting an estimated 90,000 passengers. Public sector workers across the country are demanding a pay rise of 6 percent, according to the local media.

On Monday, public service union Ver.di announced that nationwide warning strikes would take place the following day. Thousands of employees at airports and local transport companies stopped working on Tuesday.

An estimated 90,000 air passengers reportedly have been affected by flight cancellations across the country. German airline giant Lufthansa cancelled more than 800 out of its 1,600 flights scheduled for Tuesday.

Frankfurt Airport, Germany's largest airport, has already reported "considerable delays" and cancellations. Aircraft handlers and the fire brigade stopped working at Frankfurt Airport in the morning. A spokesman for the hub's operator Fraport also said that flight safety control was affected.

Major German labor union Ver.di leading the strike, which represents 2.3 million public workers in the country, is asking for a six percent pay increase for public service workers from state and local governments, with a minimum increase of 200 euros per month.