Lithuanian President Dalia Grybauskaite has become the first foreign leader to visit former Ukranian prime minister Yulia Tymoshenko in the hospital since her transfer from a prison cell.

After the Friday meeting, Ms. Grybauskaite told reporters she fears that what started as a boycott by European leaders of a summit to be held in Ukraine could become a serious crisis of trust between Kyiv and Europe. She said she wants to avert a “snowball” of mistrust from growing into an “avalanche.”

On Tuesday, Ukraine postponed a planned summit of Central and Eastern European leaders, after some of them pulled out to protest the treatment of Ms. Tymoshenko. The summit was scheduled to take place in Yalta on Friday and Saturday. About 10 EU leaders said they will not attend, including German President Joachim Gauck and Czech President Vaclav Klaus.

Ms. Tymoshenko ended her nearly three-week hunger strike on Wednesday after being moved from prison to a local hospital for treatment of chronic back pain.

Ukraine President Viktor Yanukovych is facing growing criticism about her conviction and his government's refusal to let her travel to Germany for treatment.

Some European Union member states also have threatened to boycott the Euro 2012 football championship, which Ukraine is jointly co-hosting with Poland.

Ms. Tymoshenko is serving a seven-year jail sentence after being convicted of abuse of office in a 2009 gas deal with Russia. She is now standing trial on tax evasion charges, which could extend her prison time to 12 years. The former prime minister denies the charges and says they are part of a campaign by President Yanukovych to remove his strongest political rival.

Western nations say the charges were politically motivated.