By Ben Blanchard, Abhijith Ganapavaram and Dan Catchpole

TAIPEI/NEW DELHI (Reuters) -Several Asian airlines including Taiwan's China Airlines and Korean Air said on Wednesday they were re-routing or cancelling flights to and from Europe, and about a dozen Indian airports were shut after fighting erupted between India and Pakistan.

India attacked Pakistan and Pakistani Kashmir and Pakistan said it had shot down five Indian fighter jets amid tensions over an attack by Islamist militants that killed 26 people in Indian Kashmir last month.

Images from flight tracking websites after the attack showed a long line of airlines passing over Oman, UAE and Kuwait, raising the possibility of airspace congestion.

Pakistan authorities said there were 57 international flights operating in Pakistan's airspace when India struck, and Prime Minister Shehbaz Sharif's office said in a statement India's action "caused grave danger to commercial airlines" belonging to Gulf countries and "endangered lives".

India's civil aviation ministry did not immediately respond to a request for comment on Pakistan's remarks.

In the last few days, India and Pakistan had shut their airspaces to each other's airlines. Global airlines like Lufthansa have also been avoiding Pakistan airspace.

Domestic flights in both countries were also disrupted. India's top airline IndiGo said it was cancelling 165 flights till Saturday morning. Its shares were down 1.1%.

Flights belonging to Air India, SpiceJet and Akasa Air were also cancelled as India shut several airports.

Images from Flightradar24 showed that the northwestern part of India and Pakistan's airspace was nearly free of civilian aircraft, barring a few flights.

CHANGING SCHEDULES

The changing airline schedules are set to further complicate operations in the Middle East and South Asia regions for carriers, who are already grappling with a fallout from conflicts in the two regions.

A spokesperson for Dutch airline KLM said it was not flying over Pakistan until further notice. Singapore Airlines said it had stopped flying over Pakistani airspace since May 6.

Korean Air said it had begun rerouting its Seoul Incheon–Dubai flights on Wednesday, opting for a southern route that passes over Myanmar, Bangladesh, and India, instead of the previous path through Pakistani airspace. 

Thai Airways said flights to destinations in Europe and South Asia would be rerouted starting early on Wednesday morning, while China Airlines said flights to and from destinations including London, Frankfurt and Rome had been disrupted.

Flights from India to Europe were also seen taking longer routes. Lufthansa flight LH761 from Delhi to Frankfurt took about half an hour more to reach its destination compared to Tuesday, according to FlightRadar24.

The Association Of Asia Pacific Airlines voiced concern over the impact of conflicts on airline operations.

"Apart from cost and operational disruption, there are safety concerns as GPS spoofing interfering with flight operations over conflict zones is one of highest risks the industry faces," it said in a statement.

GPS spoofing is a malicious technique that manipulates Global Positioning System (GPS) data, which can send commercial airliners off course.

(Reporting by Ben Blanchard, Abhijith Ganapavaram, Dan Catchpole and Ariba Shahid; Additional reporting by Jin Hyun Joo in Seoul, Khanh Vu in Hanoi, Bart Meijer and Jun Yuan Yong; Editing by Michael Perry, Raju Gopalakrishnan and Ed Osmond)