Feb 23 (Reuters) - Diana Shipping on Friday joined some of the world's largest shipping companies in avoiding the Suez Canal route following a spate of attacks on ships by Iran-backed Houthi militants in the Red Sea.

The canal is a key trade link between Europe and Asia, channeling nearly 12% of the global cargo. The current crisis, however, is forcing shipping companies to use longer routes, disrupting their schedules while adding to their costs.

"Suez Canal transits are running about 40% below those seen during the first half of December last year. This is partially the result of several operators including ourselves avoiding the area," Diana Shipping President Anastasios Margaronis said on a call with investors.

Falling water levels in the Panama Canal are also threatening another busy shipping lane.

"The Panama Canal is probably causing greater fleet inefficiencies than the Red Sea. Though, certainly the vessels avoiding the Red Sea are part of the story as well," a senior executive at peer Genco Shipping & Trading said on Thursday.

Transits in both canals have almost been cut in half compared with their peaks, the United Nations Conference on Trade and Development said in a report, adding that if the disruptions of key international maritime waterways continue, it could cause greater upheaval in global supply chains. (Reporting by Mrinalika Roy in Bengaluru; Editing by Anil D'Silva)