(ANSA) - BELGRADE, SEP 25 - The situation in northern Kosovo is calm but tense today, following clashes and shootings between local police and groups of heavily armed Serbian extremists yesterday. A Kosovar police officer and three Serbian gunmen were killed, and several people were injured on both sides. The news that some Pristina media outlets spread about a higher Serbian death toll, with eight extremists killed, was not confirmed. (ANSA).