KABUL — Two U.S. service members and a U.S. employee were killed today in eastern Afghanistan, pushing the American death toll this month to 29.

NATO announced the deaths in a brief statement that did not say whether the three were killed by hostile fire or an accident. It said the incident was under investigation and no further information was available at this time.

The number of American dead as January draws to a close is more than double the 14 reported in the same month last year, reflecting warnings that more U.S. casualties were expected with an influx of 37,000 coalition forces as part of President Barack Obama's strategy against the Taliban.