WASHINGTON (AP) -- House Republicans negotiating with President Barack Obama on avoiding the so-called fiscal cliff are proposing to increase the eligibility age for Medicare and to lower cost-of-living hikes in Social Security benefits.

The proposal is a response to Obama's offer last week to hike taxes by $1.6 trillion over the coming decade but to exempt Medicare and Social Security from cuts to beneficiaries.

The GOP plan also proposes to raise $800 billion in higher tax revenue over the decade but would keep the Bush-era tax cuts -- including those for wealthier earners being targeted by Obama -- in place for now.

House Speaker John Boehner said the GOP proposal is a "credible plan" for Obama and that he hopes the administration would "respond in a timely and responsible way."