Palestinian activists climbed wooden ladders leaning against the West Bank security fence Friday, carefully spray-painting "My dear Palestinian brothers" - the first words of what they say will turn into a letter stretching over 1.6 miles (2.6 kilometers) long. The letter, composed by South African human rights activist Farid Esack, contends that Israel's treatment of Palestinians living under military rule is in some ways worse than what blacks suffered during the apartheid era in South Africa. Israel has vehemently rejected such comparisons. The activists hope the words, sprayed on a stretch of the wall north of Jerusalem, will highlight opposition to the barrier. Israel started building the fence, made up of electronic fences and concrete slabs, in 2002, following a wave of shooting and bombing attacks by Palestinian terrorists. Critics call the fence a land grab as it cuts far into the West Bank in some places. The wall segments of the barrier have become a popular canvas for graffiti. For the past 18 months, the group now writing the huge letter had been spraying messages ordered over the Internet. An average message costs about 30 euros ($39), but it will cost about 16,000 euros ($21,000) to get the letter done, said Faris Arouri, who leads the 12-member team of wall artists. He said the wall artists and European supporters raised money privately to pay for the material and make a documentary about the project. The 1,998-word letter will be written in a single line. Arouri said it's being placed high on the wall so as not to cover other people's work, and will end just south of the Qalandia checkpoints where Palestinians seeking to enter Jerusalem often face long delays. The plan is to be completed by May 15.