With all the focus on Russian efforts to sway U.S. elections with social media, there are fears other aspects of Moscow's influence operations are being overlooked.Specifically, some lawmakers and experts are worried just as much damage is being done with old-fashioned, face-to-face contact, along with promises of favors and the prospects of financial reward.In order to help curtail the dangers, the vice chairman of the Senate Intelligence Committee introduced legislation Tuesday that would require all U.S. political campaigns to report any contact with foreign nationals seeking to collaborate or coordinate with candidates' election efforts."Most Americans already know that if a foreign adversary reaches out about interfering in our elections, you should report that contact," Democratic Sen. Mark Warner of Virginia said in a statement.But in a swipe at U.S. President Donald Trump, Warner added, "It's clear that some Americans haven't taken that responsibility seriously." The Foreign Influence Reporting in Elections (FIRE) Act would mandate that any U.S. political campaign contacted by foreign nationals report the contact within one week to both the Federal Election Commission and the Federal Bureau of Investigation.The bill would also require campaigns to train all paid employees on how such contact must be handled.Warner cited the recent report into Russian election interference by special counsel Robert Mueller, which found at least 140 contacts between members or associates of the Trump campaign and Russian nationals and WikiLeaks, as a key reason the legislation is needed. "The Trump campaign welcomed the help, and sought to hide that from the American people," Warner said.Separately, a panel of experts urged lawmakers Tuesday to take steps to limit the ability of Russia, China and other countries to secretly pump money into U.S. political campaigns."There's a vast amount of resources that are held by oligarchs, tycoons, businessmen, Russian companies that is available for use in dark money operations," Mike Carpenter, a one-time foreign policy adviser to former Vice President Joe Biden, told the House Foreign Affairs Committee."The most important is our campaign finance system, which is so opaque that we don't even have an inkling how much foreign dark money is sloshing around the system," he said. "It's simply all too easy and we don't know the extent."Carpenter, who now heads the Penn Biden Center for Diplomacy, said money is also likely getting into U.S. campaigns through the use of shell companies and "high-end" real estate deals.Heather Conley, the senior vice president for Europe, Eurasia and the Arctic at the Center for Strategic and International Studies, said tackling the potential abuse would require substantial changes to the way the U.S. is currently combating financial threats."We are structured to fight terrorism and terrorism financing," said Conley, who also served at the U.S. State Department under Democratic and Republican administrations."We are not structured to fight (Russia’s) malign influence and its many manifestations," she said. "We have to treat financial transparency and money laundering as the challenges to America's national security as they are."