WASHINGTON  The Obama administration on Friday backed away from an order that had prohibited insurance companies from warning Medicare recipients about the possible loss of benefits under pending legislation to overhaul the health care system.

Medicare officials set off a political storm when they tried to stop such communications last month. Under new guidelines, insurance companies can communicate with Medicare beneficiaries on pending legislation, provided they do not use federal money to do so. In addition, insurers must get permission from beneficiaries before sending them information about legislation or asking them to join grass-roots advocacy efforts.

Beneficiaries can provide consent in writing, by telephone or on a Web site, the guidelines say.

At the same time, the Obama administration cited Humana on Friday for violation of Medicare rules, saying the company had misled beneficiaries by telling them they could lose valuable benefits under the legislation being pushed by President Obama and Democrats in Congress.

The actions on Friday were the latest skirmish between the Obama administration and the insurance industry. For months, the White House and insurance companies had worked together on efforts to overhaul the health care system. But the relationship deteriorated this week after two insurance trade groups issued reports saying the legislation would cause big increases in premiums.