A Dutch plane bound for India was forced to return to the Netherlands today, and 12 passengers were arrested on landing.

AMSTERDAM (Reuters) - Dutch police arrested 12 passengers on a U.S. Northwest Airlines plane bound for India which was forced to turn back to Amsterdam’s Schiphol airport on Wednesday, news agency ANP reported.

ANP said a police spokesman said 12 were arrested, but declined to give further details due to the ongoing investigation. Dutch police were not immediately available to comment on the ANP report.

The Dutch defence ministry said earlier the pilot decided to turn back after the crew said several of the 149 passengers on flight 42 to Mumbai were behaving suspiciously.

Security has been increased at airports worldwide in the last two weeks after British police said they had foiled a plot by British Muslims to blow up planes in the mid-Atlantic using liquid explosives disguised as drinks.

“Police took off a number of people on board and took them for questioning,” the Dutch defence ministry said.

An AP report quotes a witness that the arrested passengers were “of South Asian appearance.”

A U.S. passenger named Alpa, who did not wish to use her last name, told AP television reporters she had seen police handcuff and remove around 11 men of south Asian appeareance [sic] from the plane before other passengers. She said she didn’t see what happened but heard from other passengers the men had aroused suspicion by getting out their mobile phones.

UPDATE at 8/23/06 11:17:41 am:

The flight originated in Northwest’s main hub of Minneapolis-St. Paul a day earlier, and the alarm was sounded by US federal air marshals. (Hat tip: Right Brain.)

A team of U.S. federal air marshals was on board Wednesday’s flight and, along with the crew members, observed suspicious activity shortly after take-off, according to an unnamed U.S. government official.

The official would not elaborate on the nature of the activity.

According to the official, the crew told passengers to follow the instructions of the air marshals after at least one member of the team identified himself as a marshal.

At that point, the pilot diverted the plane.