Singapore shares closed 0.22 percent lower on Tuesday, as oil prices turned mixed two days after Iran's nuclear freeze deal amid market concern as to how quickly the Iranian nuclear accord could turn into higher crude supplies. U.S. crude prices added 0.5 percent to 94.5 U.S. dollars a barrel, recouping some of the previous session's 0.8 percent decline following a weekend deal to halt Iran's most sensitive nuclear activities in exchange for some relief from sanctions. But Brent crude prices weakened 0.1 percent after ending almost flat on Monday from a slide of as much as 2.7 percent. The benchmark Straits Times Index fell 7.14 points to close at 3,173.51 points. Trading volume was 1.72 billion shares worth 1.02 billion Singapore dollars. Advancers outnumbered decliners 232 to 178, while 544 stocks closed unchanged. CIMB Research said "falling below 3,122 points would likely give the bears a boost to drag prices lower to retest 3,100 points followed by 2,990 points once more." Among top actives, Noble shares climbed 2.8 percent to a five- month high of 1.12 Singapore dollars. Coal explorer Blackwood Corporation said its directors recommended accepting a takeover offer from Cockatoo Coal. Noble had planned to sell its 51.2 percent in Blackwood, and take a 21 percent stake in Cockatoo. ST Engineering dropped 1.2 percent to 3.98 Singapore dollars. It announced today that its U.S. Shipyard, VT Halter Marine, has won a shipbuilding contract from Crowley Maritime Corporation to build two container vessels. The value of this contract is in the region of 350 million U.S. dollars. China Fishery gained 1.3 percent to 40 Singapore cents. It reported a full-year net profit of 83.8 million U.S. dollars, up 7. 3 percent on-year from 78.12 million U.S. dollars, but its revenue was lower by 8.1 percent to 555 million U.S. dollars. Among the top gainers, Jardine Cycle and Carriage rose 0.9 percent to 35.30 Singapore dollars, while Jardine Matheson became one of the top losers by falling 2 percent to 51.02 U.S. dollars. (1 U.S. dollar equals to 1.25 Singapore dollars)