As the clashes between the self-proclaimed Islamic State of Iraq and al-Sham (ISIS) and the People's Protection Units (YPG) forces in northern Syrian town of Kobani entered into third day, a severe/new explosion was heard and seen from the Turkish side of the border on Saturday.Although at first the explosion was identified as a suicide bomb attack by ISIS militants, Turkish Doğan News Agency reported that YPG militants had blown up a building located at the town's Mishtenur neighborhood, where the ISIS militants were cornered.Turkish forces further tightened security measures in the Kobani segment of the Syrian border following the explosion.Meanwhile around 500 Syrian civilians came to border in order to cross into Turkey, however, their requests were declined. Turkey currently does not accept refugees to cross into the country from areas where the situation is more stable unless they are in critical medical condition.ISIS launched its attack on YPG-held Kobani on Thursday, which started with a car bomb attack on the YPG outpost on Turkish border gate. So far, more than than 200 civilians were killed the Syrian Observatory for Human Rights said Saturday. An unknown number of armed elements from both sides were also killed in clashes."The number of civilians killed by ISIS in Kobani and the surrounding area has risen to 206, after additional bodies were found today," said Observatory director Rami Abdel Rahman, adding that most of the bodies found on Saturday bore bullet marks.In September 2014, ISIS had launched a siege on predominantly Kurdish town of Kobani that lasted for five months. ISIS was defeated as Turkey allowed peshmerga troops of northern Iraq's Kurdistan Regional Government to pass through its soil to relieve the siege. Since February, Kobani was relatively peaceful compared to other towns in the area.