By Idrees Ali, Phil Stewart and Mohammed Ghobari WASHINGTON/ADEN (Reuters) -The Houthi militia threatened a “strong and effective response” after the United States carried out another strike in Yemen overnight, further ratcheting up tensions as Washington vowed to protect shipping from attacks by the Iran-aligned movement. The strikes have added to concerns about the escalation of a conflict that has spread through the Middle East since the Palestinian militant group Hamas and Israel went to war, with Iran’s allies also entering the fray from Lebanon, Syria and Iraq. President Joe Biden said t…