Ukraine's constitutional court has delayed hearings on the legality of a presidential decree which dissolved parliament and called elections for May 27.

The delay came after five judges from the 18-member court demanded protection on Tuesday, alleging that they had been put under political pressure.

"Gross pressure has been applied," Judge Volodymyr Kampo told a news conference. "To guarantee our security, we ask to be given state protection."

The court had been due to start its hearing on Wednesday but will now not start work until April 17.

"The president's decree to dissolve the Ukrainian parliament falls within his constitutional powers," the judges said in a statement.

"Unfortunately, some famous officials and politicians publicly say it is unconstitutional, even though under the constitution it is only the constitutional court that has the right to check its constitutionality."

Political deadlock

The court has been asked has been asked to rule whether Viktor Yushchenko violated the constitution by dissolving parliament after months of political deadlock.

"[The president] is convinced that a compromise is only possible on condition of early elections" Statement from Yushchenko's office

It comprises six judges chosen by the president, six chosen by parliament and six by the legal community.

Viktor Yanukovich, the prime minister, has refused to take part in the new elections until the court has made its ruling.

The two rivals met for talks on Tuesday as thousands of Yanukovich supporters continued to protest on the streets of the capital, Kiev.

Yushchenko told the prime minister that the only way out of the political crisis was to go ahead with the elections, the president's office said.

The president "is convinced that a compromise ... is only possible on condition of early elections", Yushchenko's office said in a statement.

"Yushchenko won't compromise," Mykola Rudkovsky, the transport minister, told Yanukovich's supporters, many of whom came to Kiev from Yanukovich's support base in eastern and southern Ukraine.

"We must show the president that it is impermissible to ignore half of the country."

The president's party, Our Ukraine, which has so far failed to bring its supporters on to the streets, has announced a demonstration on Wednesday in support of early elections.