The pilot of a passenger jet was temporarily blinded by a laser beam upon landing in Rostov-on-Don late Tuesday, in the second such incident in the city within days, Interfax reported.
The plane with 97 passengers from Moscow's Vnukovo Airport managed to land safely, the report said, without identifying the airline.
An A-320 plane operated by Avianova, also from Moscow, was hit by laser on Friday and also landed safely.
No permanent damage to the pilots' vision was reported, but the incident highlights a growing trend that is prompting concerns from aviation experts.
The Federal Air Transport Agency has reported 30 similar incidents since the start of the year, a sharp increase from five in 2010. Most reports came from Rostov-on-Don and Moscow's Sheremetyevo and Vnukovo airports.
"Blinding a pilot even for a few seconds during take-off or landing is very dangerous for everyone on board," agency spokesman Sergei Izvolsky said by telephone Wednesday.
Police were investigating the two latest incidents, but did not name any suspects Wednesday, Interfax reported. Izvolsky said the laser beam could have been inadvertently sent from a nearby club.
But Sergei Kurnikov, technical director at Laser New Tec, a company that sells and installs lasers, said intentional mischief was more likely. He said planes land at a specific angle, and the laser would have to be pointed deliberately to hit a pilot's eyes.
"It's one thing to aim at a random part of an airplane when it's in the air," Kurnikov said. "But it would be another thing to target the pilot's cockpit."
He said a one-watt laser, which can be bought for $1,000 or less on eBay, can cause a blinding flash from a distance of about one kilometer, depending on the weather.
The problem is familiar to the Western aviation industry. In the United States, the number of nationwide reports of lasers pointed at aircraft almost doubled from about 1,500 in 2009 to 2,836 last year, according to the U.S. Federal Aviation Administration, which now punishes violators with fines of up to $11,000. More than 1,100 incidents have been reported this year. In April, 24-year-old Elvin Slater was jailed for a month for aiming his laser beam at a plane near Midway Airport in Chicago.
Most European countries have imposed laws that specifically ban pointing a laser beam at an aircraft. A ban on the sale of potentially dangerous lasers has been under discussion in Germany, which had 273 incidents in 2010. Australia banned possession of powerful laser pointers without permission altogether in 2008.