US Representative William R. Keating said Wednesday night that he was impressed with the extensive Russian security effort at Olympic venues in Sochi, and said that Americans who travel to the Games should be safe if they take precautions.

“With all the terrorist activity that has been the case in one of the most dangerous parts of the world, security measures are enormous, too,” Keating said at Logan International Airport, after returning from a brief Russian trip that included a tour of the security systems in place in Sochi. He said the Russian government had assembled a security force of 100,000 people, including 40,000 police and 30,000 active military personnel, along with drones and six anti-missile systems.

But Keating, citing recent suicide bomb attacks in the region, and a frantic search this week for a potential suicide bomber who may have infiltrated the city, said there is still a risk of attempted terror attacks by Islamic insurgents based in a region a few hundred miles from the Black Sea city of Sochi.

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In particular, he said, terrorists might have embedded people, or explosives, in the city before Russia imposed a strict security zone in early January that limits access to the Olympic areas. The Massachusetts Democrat also said that terror groups, who are seeking to establish an independent Islamic state in the Caucasus, could strike at targets outside the heavily guarded Sochi zones.

“These terrorists can move it out from areas that are less secure, and make a statement there,” Keating told reporters after his trip with the chairman of the House Homeland Security Committee, US Representative Michael McCaul, a Republican of Texas.

Noting that the United States, with 15,000 citizens expected in Sochi, will have the second-largest presence at the Games following Russia, Keating expressed some disappointment that cooperation between the two countries’ intelligence agencies had been limited.

“Russia is not great at sharing information with the United States,” he said. “We’re willing to do everything we can ... but it’s their country. When you do it with the US and Russia there’s room for improvement.”

Keating and McCaul were also looking into the Boston Marathon bombings, in particular what Tamerlan Tsarnaev, one of the two accused bombers, did when he spent six months in 2012 in Dagestan, the heart of the Islamic insurgency in southern Russia.

Keating said the homeland security committee is close to finishing its report on the April 15 bombings, which killed three people and injured more than 260 others. It should be released early in February, he said.

He also said it appears that Tsarnaev, who was killed after a shootout with police following the bombings, met with a recruiter for the insurgents in Russia, but did not pass their vetting process.

Keating said that he would not attend the Games in support of the Obama administration, which is avoiding the festivities because of a Russian law that criminalizes public expression of support for lesbian, gay, bisexual, and transgender relationships.

He expressed confidence that American citizens at the Olympics should be safe, but urged that they stay vigilant and pay attention to updates from the US State Department.

In addition, Keating warned Americans to expect a much greater level of scrutiny and invasiveness, including detailed security and background checks, and close surveillance of “whatever electronic equipment you bring.”

“Hopefully it won’t be too intrusive,” he said.

Keating said he spoke to members of the US joint operations center in Sochi, which, he said, had offered maximum cooperation with their Russian counterparts. The US has offered Russia the use of technology to suppress signals sent from mobile devices to set off homemade bombs, and the use of two warships and air assets. But Russia. with its own massive security effort in place, has yet to accept the help.

“We will be limited in terms of what we can do in that respect,” Keating said. “It’s their sovereign area.”