If you're traveling to London, in the coming days, be ready for intense security and delays on public transit systems.

It could be some days before transportation gets back to normal following today's terrorist blasts in the London Underground and on a city bus . British authorities asked that all travel to central London be avoided on Thursday.

Underground, buses : The London Underground (nicknamed the Tube), the city's extensive subway system, was shut after today's bombings, with very limited service expected to resume this evening. Fuller service will resume Friday, but will be limited on some lines, with some stations near the three Underground blasts remaining closed. Travelers can check on Underground service at the official Web site, www.tfl.gov.uk/tfl/service_rt_tube.shtml

Bus and rail service within and to central London were slowly resuming today, but not to areas affected by the three bombings in the Underground and that of a double-decker bus, which included Aldgate, Moorgate, King's Cross, Tavistock Square and Edgware Road.

Expect buses to be packed in the next few days since Underground service will be limited and commuters may be wary and choose buses instead of the Tube. Get bus information at www.tfl.gov.uk/buses/

Rail lines : Major railway lines and stations were operating normally Thursday afternoon except at King's Cross, a major rail/undergound station in central London near one of the blasts. See www.networkrail.co.uk for details on railway disruptions.

Air travel: For passengers at London's Heathrow airport, there were delays of about a half-hour today on arrivals and departures but it and other British airports all remained open. With the Underground service to Heathrow suspended, travelers were sharing cabs (the city's traditional black cabs set up a ride-share service) taking buses and using two trains that run between the airport and the Paddington railway station in West London, the Heathrow Express and Heathrow Connect, which were running normally.

For Heathrow airport information, see www.heathrow.co.uk/

For Heathrow Express (with service every 15 minutes), see www.heathrowexpress.com and Heathrow Connect (every 30 minutes) information, see www.heathrowconnect.com

At London's smaller Gatwick Airport, flights were operating normally and Gatwick Express training was running from the airport into London every half hour.

Taxis : For visitors to London, walking may be one of the easiest ways to go in the coming days. Or hail a cab — if you can find one. A one-mile journey in one of the city's traditional black cabs costs $7-$10, based on the current exchange rate of $1.75 to one British pound. That's for travel on Monday-Friday until 8 p.m. Travel later or on Saturdays and Sundays, and the price rises to $7.70-$12.25.

A four-mile ride will cost $17.50-$24.50 Monday-Friday until 8 p.m., jumping to $21-$30 at night and on weekends. The standard fare between Heathrow and Central London is between $70-$125.

Another alternative is "mini-cabs," the many small private companies that offer taxi service. Book them by phone through hotel staff.

Seattle Times reporter Carol Pucci contributed to this report.