BERLIN (Reuters) - The German military plans to beef up security for a U.N. peacekeeping mission in Mali by deploying a number of tethered aerostats - small airships with threat-tracking sensors - like those used by the U.S. military in Afghanistan, a spokeswoman for the armed forces said.

U.S. officials said they had provided information to the German Bundeswehr about a range of options, including the possibility of buying used aerostats built by Lockheed Martin Corp for the U.S. Army.

The dangers facing the U.N. peacekeeping force in Mali were highlighted last month when a suicide bombing killed 77 people at a military base housing government soldiers in the northern town of Gao. The attack was claimed by an affiliate of al Qaeda.

Germany is increasing its role in the U.N. force this year by deploying eight attack and transport helicopters and 350 more soldiers, to boost its contingent to around 1,000 of the total force of 15,000.

A source familiar with the U.S. deployment of aerostats in Afghanistan said the U.S. Army had 40 of the Lockheed-built Persistent Threat Detection System airships on hand that could be sold at a discount to other countries. No immediate information was available about the likely cost.

Germany could also purchase new lighter-than-air surveillance aerostats built by Lockheed or other suppliers, or opt to lease the equipment, an additional source said.

Aerostats could be used to provide radar surveillance to detect threats such as drones or surface targets.

Until they are acquired, the military will erect a 30-meter (98-feet) surveillance tower mounted with sensors, said Lieutenant Colonel Simone Gruen, spokeswoman for Germany’s joint forces operational command.

The German air force is sending the radars used on the NBS MANTIS air defense system, built by Rheinmetall for protecting the forward operating bases of the German military in Afghanistan.

For now, only the sensors will go to Mali, but the German military could send the full air defense system, which includes counter-rocket, artillery and mortar systems, depending on the threat situation in the African country, said one of the military sources.

Current plans call for the aerostats to be put to use in Mali around 2019 or 2020. However, one U.S. official said sales of excess defense equipment could occur quickly.

“If Germany wants the aerostats, they can definitely get them sooner than 2019 or 2020,” added a second source.

Lockheed had no immediate comment on the matter.