LONDON (Reuters) - British Prime Minister Boris Johnson spoke to European Commission President Ursula von der Leyen on Saturday to try to secure a breakthrough in the Brexit talks. Below is a statement from the two leaders: “In a phone call today on the ongoing negotiations between the European Union and the United Kingdom, we welcomed the fact that progress has been achieved in many areas. “Nevertheless, significant differences remain on three critical issues: level playing field, governance and fisheries. Both sides underlined that no agreement is feasible if these issues are not resolved. “Whilst recognising the seriousness of these differences, we agreed that a further effort should be undertaken by our negotiating teams to assess whether they can be resolved. “We are therefore instructing our chief negotiators to reconvene tomorrow in Brussels. “We will speak again on Monday evening.”