A tanker was approached by 2 medium sized skiffs whilst underway 125nm southeast of Tema. The tanker made evasive manoeuvres and altered its course to 270° and increased to full speed. The 2 skiffs increased their speed and continued to pursue the tanker. The crew noticed that both skiffs had up to 10 persons on board but were unable to identify if there were any weapons or ladders onboard. After chasing the tanker for 30 minutes the skiffs abandoned their pursuit.