not allow any foreign troops on its soil, while the country cannot join military alliances. Moldova and the Kozak memorandum was a key issue at the OSCE ministerial meeting in Maastricht in December 2003, and disagreement between Russia on the one hand, and the EU and the US on the other on Moldova, was one of the principal reasons why a final joint declaration was not adopted after the meeting. 2004 crisis In the summer of 2004, a crisis erupted over the issue of Romanian-language schools in Transnistria. It led to a breakdown in negotiations and economic retaliations by both sides. The issue was resolved by compromise: The PMR government gave the schools autonomy and the schools formalized their registration with the PMR Ministry of Education. Ukraine-sponsored talks In May 2005, the Ukrainian government of Viktor Yushchenko proposed a seven-point plan by which the separation of Transnistria and Moldova would be settled through a negotiated settlement and free elections. Under the plan, Transnistria would remain an autonomous region of Moldova. The United States, the EU and the PMR itself expressed some level of agreement with the project. In July, Ukraine opened five new customs posts on the PMR-Ukraine border. The posts, staffed by both Moldovan and Ukrainian officials, are intended to reduce the hitherto high incidence of smuggling between the breakaway state and its neighbors. 5+2 negotiation format Beginning in 2005, multilateral talks were held on the subject of Transnistria. The 5+2 in the name refer to Moldova, Transnistria, Ukraine, Organization for Security and Co-operation in Europe and Russia, plus the European Union and the United States as external observers. The talks proved to be a failure. They restarted in February 2011, in Vienna. In April 2011 Russia agreed theoretically to create an autonomous region of Transnistria inside the Republic of Moldova, but there were many other problems to be solved in the talks. Russian invasion of Ukraine After the annexation of the Crimea by Russia in March 2014, the head of the Transnistrian parliament asked to join Russia. On April 26, 2022, authorities from the Transnistria region said two transmitting antennas broadcasting Russian radio programs at Grigoriopol transmitter broadcasting facility near the town of Maiac in the Grigoriopol District near the Ukrainian border had been blown up and the previous evening, the premises of the Transnistrian state security service had been attacked. Observers feared targeted provocations to give Russia