(Reuters) - The United Nations envoy said on Tuesday that the warring parties in Yemen have agreed to extend for an additional two months a truce that expires on Tuesday, despite international pressure for an expanded agreement that could benefit from the longest period of relative calm in nearly seven years. "This extension of the armistice includes a commitment by the parties to intensify negotiations to reach an expanded armistice agreement as soon as possible," Hans Grundberg, the special envoy to Yemen, said in a statement posted by his office on his website. Sources had told Reuters that Grundberg had been pressing for a six-month truce with additional measures, but the mistrust was deep between the two sides and they had complaints about the implementation of the current truce agreement. US and Omani officials also intervened with the warring parties to support Grundberg's proposal after President Joe Biden's visit to Saudi Arabia last month, where he announced, after bilateral talks, an agreement to "deepen and extend" the armistice. The conflict, between the Saudi-led coalition and the Iran-aligned Houthi movement that controls northern Yemen, has killed tens of thousands and pushed millions to the brink of starvation. The internationally recognized government accused the Houthis of intransigence in talks to reopen the main roads in the disputed Taiz, while the Houthis accused the coalition of failing to deliver the agreed number of fuel shipments to Hodeidah and some commercial flights from the capital, Sanaa, two areas under Houthi control. "In the coming weeks, I will intensify my contacts with the parties to ensure the full implementation of the commitments of all parties to the armistice," Grundberg said. He added that the extension of the truce would provide a mechanism for paying the salaries of public sector employees, opening roads, increasing the number of flights from Sanaa and the regular flow of fuel to Hodeidah. The United Nations is also pressing for a permanent ceasefire in order to resume talks to reach a lasting political solution.