How do you splice fiber optic cable under water?

Yesterday an undersea fiber optic cable cut or other damage wiped out data communications including Internet between parts of the Middle and India, and Italy. My question is, if you have a broken cable comprised of hundreds or thousands of fibers lying along the sea, how do you repair it? Can you splice in a pressurized dive suit underwater? Is it simply a matter of slogging through a thousand splices, hoping you have enough slack? (How do you pull a thousand-mile long cable along the sea floor if you need more slack anyway?)