Ukraine's one-time "Orange Revolution" allies said yesterday they had reunited in opposition and called for early parliamentary elections.

The development comes amid a growing standoff between the increasingly sidelined pro-Western president and Ukraine's powerful Russian-leaning prime minister.

President Viktor Yushchenko's party Our Ukraine and the party of opposition leader Yulia Tymoshenko signed an agreement late on Monday on creating a joint opposition force in parliament, a statement said yesterday.