Berlin, Oct 25 : One sailor has died and four remain missing after two cargo ships collided on Tuesday in the North Sea off the German coast. Two people were rescued, the Central Command for Maritime Emergencies (CCME) and the German Maritime Search and Rescue Service (DGzRS) said. The collision between the cargo ships Polesie and Verity occurred around 22 km southwest of the island of Helgoland and 31 km northeast of the island of Langeoog in the North Sea, Xinhua news agency reported. The smaller freighter Verity is presumed sunk after the collision. The second freighter, Polesie, is understood to be still seaworthy and the 22 people on board are "unharmed according to current knowledge". "The airspace above the accident site is closed within a radius of ten nautical miles in order not to obstruct the search operation," the maritime rescue services said in a statement. Numerous ships as well as a German navy helicopter are involved in the rescue operation. A sensor aircraft was also flying over the area to "obtain further information", the statement said. The area was currently experiencing strong winds and waves of up to three meters. The search is also supported by a cruise ship, with doctors on board who could provide medical care. "My thoughts are with the crew members and their families," Germany's Transport Minister Volker Wissing said on Tuesday. "I thank the rescue teams, who have been in action since early morning. They are doing everything they can to rescue the missing." The 91-meter-long Verity was on its way from Bremen to Immingham in the UK. The 190-meter-long and thus significantly larger Polesie, registered in the Bahamas, was heading from Hamburg to La Coruna in Spain, according to the statement. /IANS