Akhir 29, 1432 / April 03, 2011, SPA -- German Foreign Minister Guido Westerwelle announced Sunday he would step down in May as leader of the Free Democratic Party (FDP), the junior partner in Chancellor Angela Merkel's ruling coalition, according to dpa. But he said he intended to stay on as foreign minister. The FDP national executive is to meet in Berlin on Monday to consider his offer, which could lead to a cabinet reshuffle, but is not expected to shake the Merkel government. Westerwelle has faced relentless pressure all week to resign his leadership of the pro-business party and let someone else take on the task after its vote share crashed in two state elections on March 27. In the biggest of those polls, the FDP share was halved in the state of Baden-Wuerttemberg to 5.3 per cent, compared to five years ago. Party activists have blamed Westerwelle, FDP leader for 10 years, for the decline. "I can assure you that this is obviously an unusual day, an unusual day even for me," said Westerwelle, 49, tensely, saying his party needed to hand over to a new, younger generation. "This is hard to do because one is passionately involved after 10 years as party leader," he said. Federal Health Minister Philipp Roesler, 38, seen by Berlin insiders as the front-runner to replace Westerwelle as party leader, called in an interview for a change in direction at the FDP. "It's a question of regaining lost credibility. For the sake of the party, we have to work together," he told the newspaper Bild am Sonntag. Whoever is picked by the FDP inner circle as new leader is expected to rule de facto from the coming week, with a party conference in May likely to rubber stamp the selection. Westerwelle said he would remain foreign minister, but made no mention of keeping his title of deputy chancellor. The new party leader would probably acquire that rank and be free to chose which cabinet portfolio to take as his own. The foreign minister has faced low popularity ratings among Germans across the political spectrum for a year. Conservatives were upset last month when he instructed German diplomats to abstain in a UN Security Council vote on imposing a no- fly zone over Libya, breaking ranks with the western alliance. Critics say Westerwelle's attack-dog style of politics helped him advance as an opposition politician, but antagonized many Germans when he became foreign minister and continued to stridently demand tax cuts for small business and the middle class. Aides said he worked the phones from Berlin all Sunday, speaking to former provincial supporters, before accepting that his post as party leader was untenable. The three opposition parties, the Social Democrats, the Greens and the Left, called for Westerwelle to resign the Foreign Ministry as well. "He can't stay on in the one post and not the other. This is a matter of German standing in the world," said Renate Kuenast and Juergen Trittin, the Greens parliamentary co-leaders. The German media, who have given Westerwelle persistently negative coverage, have already identified potential replacements as foreign minister, including Alexander Graf Lambsdorff, 44, a member of the European Parliament and a diplomat by training. Westerwelle's departure leaves Economics Minister Rainer Bruederle, 65, who is a deputy leader of the party, in a shaky position, with his support within the party uncertain.