* Gas-directed rig count climbs to near six-month high * Horizontal rigs rise for 2nd time in 3 weeks * Oil rig count down 4 to 1,361, 3rd drop in 4 weeks NEW YORK, Sept 13 (Reuters) - The number of rigs drilling for natural gas in the United States climbed by seven this week to near a six-month high of 401, data from Houston-based Baker Hughes showed on Friday. It was the second straight weekly gain for the gas-directed rig count, which posted an 18-year low of 349 in late June. The count is the highest since March 22, when it stood at 418. Recent rig count gains - the count has risen in eight of the last 12 weeks - have stirred concerns that new investment in gas pipelines and processing plants, particularly in the East, are allowing producers to hook up more wells and pump even more supply into an already well-supplied market. Gas futures prices on Friday, which were up 2.2 cents at $3.66 per million British thermal units just before rig data was released at 1:01 p.m. EDT (1701 GMT), gained 1.5 cents after the report. The oil-focused rig count fell for the third time in four weeks, dropping four to 1,361. The oil rig count hit a nine-month high of 1,413 in mid-June, Baker Hughes data showed. The oil count is down 52 rigs, or 3.7 percent, from the same week last year. Baker Hughes reported horizontal rigs, the type often used to extract oil or gas from shale, picked up one rig to 1,076, the second gain in three weeks. The horizontal count is down almost 10 percent from the record high of 1,193 set in May 2012. Despite recent gains, drilling for natural gas is down 57 percent since peaking in October 2011 at 936. But so far gas production has not slowed much, if at all, from the record high hit last year, boosted by the associated gas produced from more profitable shale oil and shale gas liquids wells. The U.S. Energy Information Administration still expects gas output in 2013 to hit a record high for a third straight year.