After two female suicide bombers brought down two planes in 2004, killing 88 people, the authorities spoke of stricter security measures at airports including Domodedevo Airport, where the bombers had boarded the aircraft.
A deadly Moscow metro bombing later that year inspired renewed promises of improved security.
Bombs planted on tracks that derailed Nevsky Express trains in 2007 and 2009 and twin suicide bombers who killed 40 in the Moscow metro last year sparked new rounds of pledges to beef up security.
So the question now is what the authorities hope to accomplish by tackling security once again after a suicide bombing at Domodedovo Airport in January killed 37. If anything, officials and experts said in interviews, the latest attack only underscores the many loopholes that remain in transportation security rules after years of deadly attacks.
The majority of terrorist attacks that have taken place outside the North Caucasus over the past decade have targeted transportation facilities. Existing legislation plays a part, experts say, because it merely punishes attackers but does little to prevent them from striking. In addition, they say, the current rules are ineffective, and the various agencies overseeing transportation security cooperate too little with one another.
Federal Security Service chief Alexander Bortnikov acknowledged that transportation infrastructure remains vulnerable to attacks.
Recent checks "have proved that transportation facilities are among the principle targets of sabotage and terrorist attacks because of their high level of vulnerability," Bortnikov fumed at a February meeting of the National Anti-Terrorism Committee, which is charged with coordinating anti-terrorism efforts between government agencies.
An urgent problem is the lack of sufficient security measures in certain areas of airports, he said, according to a Kremlin transcript of the meeting. The Domodedovo blast took place in the international arrivals hall, an unrestricted access zone at the airport and at most airports around the world.
President Dmitry Medvedev sought to reassure the public after the January attack, making a televised tour of the Okhotny Ryad metro station to inspect security equipment installed after the 2010 metro bombings. A visit to the metro station this week found a metal detector and X-ray screening machine standing unused behind a metal barrier.
Confusing legislation contributes to the fuzzy security situation, because a 2007 law makes the owner of a transportation facility liable for security, with harsh punishments for negligence spelled out in the Criminal Code. But a 2010 law requires law enforcement agencies to oversee even privately owned transportation facilities, like Domodedovo Airport.
Federal aviation rules also oblige airport owners to ensure the deployment of private security guards and installation of screening equipment, but they give no specifics about the required amount of manpower or X-ray screeners, metal detectors and surveillance cameras.
"The laws need to be systematized and legal gaps filled," Sergei Yuryev, president of the National Association of Aviation Law, said in a telephone interview.
After the 2010 metro bombings, the government allotted 46 billion rubles ($1.6 billion) for a four-year program to equip every transportation facility nationwide with security equipment. But the program, to be carried out jointly by facility owners, Russian Railways and the FSB, provides no specifics on equipment.
There is also currently no differentiation between the various types of transportation, although the Transportation Ministry has drafted four separate sets of rules for automobile, railway, aviation and sea transportation, senior ministry official Yury Shapovalov told The Moscow Times.
The draft is awaiting a Justice Ministry check, he said.
A Transportation Ministry proposal to finance security at 49 main airports and 63 seaports nationwide from state coffers is also stuck in the government, this time at the Finance Ministry, Shapovalov said.
Inquiries submitted to the Justice and Finance ministries on Feb. 17 went unanswered as of Tuesday.
Russian legislation does not fully comply with global standards on transportation security and fails to fulfill the country's international obligations, Viktor Voitenko, a member of State Duma's transport committee, said at a recent security conference in Moscow.
Preflight screening and seaport security are two areas where Russia falls short compared with international standards, but elsewhere the situation is worse, the deputy head of the Federal Agency for Monitoring Transportation, Vladimir Chertok, said in an interview. He did not elaborate.
There is little to no cooperation between state agencies on transportation security, industry insiders said.
Bureaucratic chaos sometimes even results in agencies issuing contradictory instructions on the ground, Duma Deputy Voitenko said.
Voitenko was echoed by Chertok, who called "the lack of timely information the main problem in fighting terrorism."
The government's 2010 transportation security program calls for the creation of a system of cooperation between agencies, but it gives few details.
The current system does little to motivate transportation facility owners to pay attention to security.
Chertok pointed out that official security checks at private facilities, like Domodedovo, are rare and predictable. Moreover, a 2008 law bans officials from examining private enterprises more often than once every three years.
The law, ordered by President Dmitry Medvedev, is aimed at protecting businesses from bribe-hungry officials. But Chertok said it has led to unexpected drawbacks for security. "If a check is conducted once every three years, then the owner can simply correct all the shortcomings right before the check," Chertok said.
Moreover, state regulations are not detailed enough, which means transportation facility owners can establish their own security guidelines and officials are hard-pressed to punish them for negligence, said Shapovalov of the Transportation Ministry.
"A conflict of interests arises here between the need to provide security and the pursuit of profit," said Vladimir Lopatin, a private lawyer who dealt with security issues when working at the Duma and the Prosecutor General's Office.
He said owners and officials also do not do enough to tap available Russian technology.
"It grieves me to see that mainly imported technology is used, even though our country's applied science has achieved good results," Lopatin said.
For example, customs officers at Domodedovo use a U.S.-made passenger screening system that costs twice as much as one developed at the Novosibirsk Institute of Nuclear Physics, said Yury Ukraintsev, a senior researcher at the institute.
A screener called ProVision, formerly known as Safe Scout, by a U.S. company, costs $300,000, while a Novosibirsk-made Sibscan can be obtained for $150,000, Ukraintsev said in a telephone interview, adding that his institute's device is also more efficient.
An inquiry submitted to Domodedovo Airport on Feb. 9 went unanswered.
A more exotic recent anti-terrorism measure put forth by the government orders architects to design buildings in such a way as to decrease the possibility of a bomb being planted on the premises.
But the decree, signed by Prime Minister Vladimir Putin in mid-February and due to be drafted into a bill, apparently leaves out transportation infrastructure. It also does nothing to boost security at facilities built before Putin's order.
In this situation, a passenger's best bet appears to be to look out for themselves. Safety could be boosted significantly if travelers would remember to scan their surroundings for suspicious people or objects, Chertok said.
"People have become more attentive. They telephone relevant agencies and give information," Chertok said. "This brings positive results, even though a large part of it is spam."