Copenhagen's Metro reported recently a 25 percent drop in the number of passengers. The drop is caused by terror attacks on subway in London.
Some 2.1 million passengers used the Danish capital's subway system last month, down from 2.8 million in July 2004.
Anne-Grethe Foss, of Metro operator Oerestad Development Corporation, also said good weather and technical problems on the capital's commuter train system prompted people to use their bicycles or cars instead.
In the two days after the July 7 attacks that killed 56 people in London, the operator saw a drop of 14,000 people each day.
Denmark has been singled out on extremist Web sites as a possible terror target following the London bombings because it has about 500 troops in Iraq, the AP reports.
Copenhagen's 11-kilometer (7-mile) subway opened in 2002.