Soccer-Celtic sign Schalke striker Pukki

Aug 31 (Reuters) - Celtic have signed Finnish international striker Teemu Pukki from Germany's Schalke 04 on a four-year deal, the Scottish champions said on Saturday. No fee was disclosed for the 23-year-old in the announcement on the club's Twitter feed. Celtic, who are in a tough Champions League group H with former winners Barcelona, AC Milan and Ajax Amsterdam, also signed Israel midfielder Nir Biton from FC Ashdod on Friday on a four-year deal. (Reporting by Alan Baldwin, editing by Patrick Johnston)