The New Zealand stock market began trading modestly lower Monday after becoming the first market in a developed economy to open since Friday's terrorist attacks in Paris killed 129 people.

The country's benchmark S&P/NZX 50 index was down 0.6 percent in early trading. Among stocks to decline was the national carrier, Air New Zealand, which was trading down 1.4 percent.

The market opened as France launched air strikes on the Islamic State group's stronghold in Raqqa, Syria. The Islamic State claimed responsibility for the attacks.

Police have announced seven arrests in the case and say they're hunting for more suspects.